Is it because those companies see their profits from such patents as larger than the occasional cost of buying off a patent troll?
Yes. Also, defending yourself from these types of patent issues discourages competition by greatly increasing the cost to enter the market.
If we religion nuts really thought the world was ending, we wouldn't be asking any earthly powers stupid questions. We would be down on our knees asking God for mercy. Let's face it, if a rogue planet is about to collide with earth, there's nothing else you can do.
So the world is ending on Sunday? I need to pack!
The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh