Ok, I'm certain I'm going to get modded into the stone age because, well, that's what happens on Slashdot nowadays so let's just get on with it.
First, the VAST majority of the patents involved in a mobile device are FRAND patents that are required for the phone to be, you know, a phone (plus the wifi and whatnot). And those patents are licensed at INCREDIBLY low rates per device because the inventor knows that they are going to make back their investment in the long run because EVERY device uses the patent. That is the value in a FRAND patent. That is why companies work so incredibly hard to get their invention involved in an industry standard - the value is long term. The value is in a steady stream of income, even if it is small per device, from everyone.
The other type of patents are the ones which Apple is enforcing in this case - non-FRAND patents. They are not, in any way, an "industry standard" and thus other manufacturers have a choice to a) pay whatever licensing fee they can negotiate with the patent holder or b) invent around it. Since it isn't REQUIRED, option b is available.
Now, the patent holder has the benefit that they are under no obligation to license the patent in question. With a FRAND patent, they do not have that choice. By agreeing to be part of an industry standard, the company agrees to license the patents at FAIR and REASONABLE rates and NON-DISCRIMINATORY. That means, EVERYONE can license the patent - the patent holder has no right to prevent a company from licensing it - and the rates MUST be fair and reasonable which equates with "very low because they make it up in bulk since everyone needs to license it." Thus, the 250,000 patents.
What trips up most people is the idea of "industry standard". It isn't a "well, everyone does it so it's standard". It is "companies pitched to be included in an industry standard that was being established by a board and went through an extensive review and development process". It is a legal term, not a description.
Apple's patents that they are enforcing aren't FRAND. They are under no obligation to license them to anyone. They are entirely within their right to not license them to anyone. Conversely, Samsung is also under no obligation to use them. They can agree to pay to license them or, alternatively, they can design around them and not infringe the patents.
Well, actually, there's another option, which Samsung opted for - infringe the patents and then drag the issue out in court and wage a PR war of misinformation. Most companies, however, either agree to license the patents or, if they can't reach an agreeable rate with the patent holder, design around the patents instead.
Now, feel free to mod me down since I'm clearly an Apple fanboy despite speaking the truth and I've dared to impugn the honour of Samsung...
Oh, and lastly, can we SERIOUSLY get one or two story summaries that aren't clear and obvious flamebait? This site has become total shit in recent years and I see no recovery... sigh...