Or: "IBM just screwed me over, but if I sue there's a chance I'll lose, and the penalty for losing is orders of magnitude greater than I could possibly afford. Guess IBM gets to keep screwing me over."
"IBM is suing me using twenty overly broad patents, most of which don't even apply. I'm pretty sure I can win in court, but it doesn't matter because the legal costs will bankrupt my company long before I can get a final decision. May as well sell out for pennies on the dollar - it's my only choice."
The amount of times I've seen breaches of e.g. open source licenses dwarfs the number of patent cases I've seen. Generally, the creator has no recourse, because they can't prove it most of the time (closed-source product), nor can they afford the court costs if they wanted to, so it just slides. Sometimes changes are made (e.g. GPL-using code open-sourced), but often they aren't, and it's largely because the offended party is small and can't properly defend themselves, so it isn't worth it.