Short answer: They aren't capable in most cases.
Long answer: The original creditor can usually be expected to be able to produce proper documentation of a loan or other debt, the contract with your signature, monthly invoices, and an ongoing record of payments made (if any). A court will always expect them to have all of this: no contract, no proof, no debt. When they do have it, a lawsuit against you will usually be little more than a formality: the creditor will win the judgment swiftly, as they should.
If someone says you owe them money and you start making payments on it, that's good enough for a court that you admit you owe it. If any contract is objectionable but you go ahead and start fulfilling your side of the agreement, you've just accepted the contract as written. Similarly, if a debt is past the statute of limitations but you make a payment on it, the clock restarts and the debt is again valid and actionable in court.
When one defaults on a payment owed, the typical process (here in the United States) is that a notice gets sent out once a month. If no payment is forthcoming, the account gets kicked to a collection department after 60 or 90 days. Big businesses often have an internal collections department, but usually this is outsourced to a collection agency that handles further notices and phone calls for a fee. Eventually, defaulted accounts that are uncollected for however many months are bounced back to the original creditor. These are unlikely to be recoverable (either due to chronic insolvency, unreachable debtors, inadequate/lost documentation, etc). The creditors know that if documentation is deficient they wouldn't win a lawsuit, or if the documentation is intact but the debtor has no assets to seize, so they either write the debts off or sell them in huge batches to "junk debt" collectors for pennies on the dollar so they at least recover something.
This is where those spreadsheet lists come in. Sometimes the batches might contain some documentation, rarely all documentation, but typically they do not contain anything a diligent court would accept. Documentation gets partially or totally lost, corrupted, or destroyed all the time. Junk debt collectors don't care, as it's not usually needed. They choke local courts each year with hundreds of thousands of lawsuits alleging debts owed. They get away with this because most people never even bother to file a response to the complaint, and then a motion for summary judgment is granted by default. Then they motion for garnishment, and win. Hell, I've even seen cases where people respond with a letter asking the court for leniency, but that's an admission that they owe the debt: a motion for summary judgment follows immediately after. There have been accusations that people are never even properly served with lawsuit papers and never know about it until the lawsuit is lost, and that certainly happens sometimes. Most of the junk debt isn't even valid, or was already paid off but the documentation doesn't show this, or it's so old that it's past the statute of limitations and can't be collected by court order, etc.
Many collection agents (which has one of the highest turnover rates of any job in the country, hence incompetent and poorly-trained staff) threaten, insult, harass, call out of permissible hours, call you at work, etc. The biggest thing is that they LIE, particularly about being able to garnish your wages when a court has not already issued a judgment, or stating that they can sue you when the debt is past the statute of limitations. All of these actions are violations of the Federal Debt Collection Practices Act. The FDCPA is actually quite good, and lays out all the ground rules for what debt collectors are and are not permitted to do. When you can pinch them on any one of these FDCPA violations, it's an automatic $1,000 fine plus attorney fees, so it's excellent leverage. Call recorder apps are a must, provided you're in a state where call recording is legal
A handful of people challenge the suits in court (most without attorneys, since they can't afford them, but if you're intelligent and do your research you can do just fine representing yourself), and those people can often prevail except for when judges are prejudiced against debtors. When the junk debt buyers do try to prove it in court, they produce falsified documentation, a boilerplate copy of the loan agreement that the debtor never signed or even received, and robo-signed affidavits (sometimes by people who don't even exist) claiming that they have first-hand knowledge of the documentation in question (which is a requirement for a document to be entered into evidence). Even some of the courts are getting fed up with their bullshit.
Pretty much all of these boilerplate contracts now obligate borrowers to use private arbitration instead of a court in case of any dispute. This was initially a weapon against consumers, as the arbitration organizations (AAA and NAF, primarily, but also JAMS) were ruling in favor of the creditors and junk debt buyers in over 99% of cases. They got their pants pulled down and spanked by regulators, and now NAF refuses to take any consumer debt cases. AAA still does but they are anti-consumer. JAMS is much more even-handed, and not brutally prejudiced against "pro se" (self-represented) people. After all that went down, arbitration can more often than not be a consumer shield. When sued in court by junk debt buyers, the debtor can elect for private arbitration, and these agreements almost always say that the CREDITOR pays the arbitration fees. It then becomes the creditor being obligated to either walk away, or cough up a few grand in arbitration fees to collect on the debt. The junk debt buyers almost always walk, and if they choose not to they frequently lose because of the aforementioned inadequate documentation. Note that the original creditors, like Citibank or Discover, will slug it out in arbitration or in court indefinitely: they will spend $100,000 in court costs and in-house attorney salaries to collect on a $1,000 debt, because they won't stand for having a reputation of backing down to debtors, and they can almost always back up their claims with legitimate documentation.
Training shoes don't have high heels.
Maybe yours don't!
Let me preface this by saying that I believe in giving credit where credit is due, so this will not be an anti-Apple comment despite the fact that I am not an Apple fan. At all.
Apple earned such a strong position on, I believe, two fronts.
The first and foremost prong being a robust philosophy, appealing to users who like to think of themselves as independent thinkers. This was really cemented by their famous Super Bowl commercial rejecting the Orwellian drones: a marketing coup, to be sure, since Apple is and always has been rabidly anti user freedom. People who identify with this take strong pride in their allegiance to Apple. This is brand loyalty. The gadgets Apple makes really take a backseat to the "Why" that people perceive about them. Users display the logo proudly. As Simon Sinek pointed out, Apple's laptops and notebooks are the only major brand where having the lid open displays the logo right-side up to observers.
The second prong is that they have repeatedly entered industries where they did not conventionally even belong, brought novel innovation that both revolutionized those industries and, for a time, allowed the company to dominate them. Take cellphones as the prime example: before the iPhone, there were a handful of shitty flip handsets available, the capabilities and limitations entirely dictated by the phone service carriers. Smartphones did come to exist, but were a niche market almost entirely confined to business people using them as work phones, and a handful of bleeding-edge tech geeks. But when Apple (a computer company) entered the cellphone business, THEY dictated what the phones would do, and the carriers were given the option to cede control or watch the iPhone debut on a different carrier. AT&T accepted, the entire industry was flipped on its head, and now iPhones and Android devices are THE dominant devices.
As a side note, yes: Steve Jobs was famously a lunatic control-freak. But he was a visionary, and together he and Wozniak ensured that his vision stayed consistent by controlling both the hardware and the software, and he wasn't afraid to enter what are nominally considered unrelated markets. With the death of Jobs, the company remains in a strong financial position but may lack the leadership to continue to innovate.
You knew the job was dangerous when you took it, Fred. -- Superchicken