You get logs on the Mac and plenty of diagnostic tools including dtrace. If the phone is broken you take it back to apple and they give you a new one, but there are diagnostic logs on that too that you can get off it.
Sounds like you're a typical nerd who gets asked to support apple gear and you're out of your depth, so just say "it's crap" because you don't understand it.
Whilst the iphone is pretty, what apple actually sells is a device you don't have to babysit, that does what it says on the box in a manner that is both attractive and pleasant to use.
The reason many people, myself included by apple gear is because I have spent the past 20 years babysitting computer shit because it half does what it says, needs care to use to ensure it doesn't get malware, etc. I'm fucking over it. I don't care about the theoretical reduced flexibility if the device does what I actually want it to do, and doesn't need babysitting.
Being pretty is a bonus, not the primary motivator.
Because stamping out 100 million copies of a single model (e.g., iphone) is a LOT more cost effective than trying to tool up to stamp out 10 million copies each of 10 different models. Which means that they can increase their profit margin or increase feature set at the same price as they see fit.