As for tablets: they may not have been the revolution that some people hoped for, but the lock-in to a walled garden happened anyway with the iphone. Apple has done more long-term damage to the computer industry than anybody else by convincing way to many software authors - who should really know better - that paying to write and publish software is sane.
Instead of fighting this when it was small, we are now faced with a future where even the hardware can work against the user who wants a true General Purpose Computer. We've already seen BIOS lockouts such as the recent thinkpad "boot guard" idiocy. It will get really bad once we start to see Intel "SGX" and the "trusted execution environment" it is intended to enable[1]. So now we get to fight at the hardware level, too.
As for using vulnerabilities to root the device - that is not a strategy to fight this, and merely cedes the fight to the people that are afraid of what it means to be "turing complete".
Unfortunately, I suspect that we are too late. Fighting this trend now requires sacrifice. Stop giving any money to any business that uses these anti-user technologies. Yes, that includes Intel and many others. Stop writing software or making embedded products that rely on these kinds of features. Yes, this might mean quitting a nice job. No, I expect instead that the people that should know better will continue supporting the enemy by buying their products. I expect they will stay on as collaborators.
[1] this should scare anybody that wants a future where that still has general purpose computers: http://www.arm.com/images/GP_Standardization_500.png