There are some lawyers (well at least one) that make a business out of sueing companies over often bogus patents, as part of the settlement they take cash and/or patents from the companies, thus increasing their arsenal and moving on to the next guy.
At my previous company we got hit by one of these characters. He sued us for a particular design, not one that we directly infringed on, but a device INSIDE a chip that we were using from Philips semiconductor or something. the thing is, there was prior art, and the patent was invalid anyway. He didn’t sue Philips that actually made the chip that infringed on his bogus patent, for a number of reasons: 1. Philips likely had enough money to successfully defend the case. 2. The philips chip cost only a few dollars per unit, if he wanted a cut he couldn’t get much, our hardware went for a couple thousand dollars per board - so he went for a cut of that. We were also smaller and less able to defend against the obviously bogus claim.
The guy had managed to extort money from many companies this way, it was his business, though of course on paper he claimed to be developing this technology in an attempt to keep the patent valid.
It is very sad the way patents are abused in North America.
Sadly, I think we had to pay the guy off eventually, because we were getting killed by legal fees - that of course was his plan all along, knowing that the patent really was worthless, and he being a lawyer didn’t have to suffer the same level of expense.