My feelings and desires affect how I vote, and voting affects legislation as well as such things as who gets appointed to the Supreme Court. (and given our legal system, courts determine law as much as legislators do)
I think it is awful that manufacturers of devices have that level of control of who can sell apps to run on them, and I certainly hope enough other people do to affect law. I'm old enough to remember when you could only buy a (landline) phone through Ma Bell, and luckily the law -- via courts of course -- stopped that eventually.
This is very similar, but in my opinion the current issue is a good bit worse that AT&Ts monopoly.
If I make a device, you should not be able to force me to support your software running on it. That seems fundamental.
As a consumer, I can be disgruntled that my chosen platform is not as flexible as I wish. I can either throw a fit and lobby congress to force Apple to open its gates, or wait a year or two for my phone to slow down and pick up an Android device. In fact, this kind of migration occurs in both directions on a regular basis. Only religious loyalists stick with a single ecosystem without examining the tradeoffs they're making, as a general rule.
Your purchasing decisions are not mutually exclusive with action from courts and legislators and voters and such. And, especially if you take into account that market theory as well as game theory tends to view individuals as rational agents pursuing self interest (1), a pure free market approach simply does not effectively curtail monopolistic and otherwise anti-competitive behavior of corporations.
[1] as a baseline, anyway.
