A couple million dollars would bankrupt the average freelance developer, some many times over. A couple million dollars to any of those companies is negligible. I'm not saying that money is no object, but on the other hand, that Google or apple or whomever allows patrons of their store to be bullied like this is, in my opinion, an embarrassment. It not only shows a lack of concern, but it also loses them money because the apps in question probably have to be pulled from the store. I might be off base but I absolutely think that any of those companies could sue these trolls for their behavior. Instead they seem to be showing that they only care about number one.

If the same plaintiff is suing the a bunch of different developers over the same alleged infringement then I believe the defendants could request that the cases be combined?

If they systematically defended these clients it would not take long for the patent trolls to seek greener pastures. After all, patent trolls are in it to get a settlement or payout. If there's a class of lawsuits where they have no hope of seeing any money, they would steer clear.

Those three companies all have tonnes of cash on hand! Its the right thing for them to do, also!