Nice theory, except I ALREADY TRIED THAT with the RIAA and haven't bought a single disc from an RIAA artist (nor have I pirated from them) in a decade. What did we get? "Our sales are down and since our shit don't stink it has to be those filthy piratez! We want even more draconian laws!" which they get. So you see your argument doesn't hold water, because the *.A.As will just trot out some trumped up bullshit piracy numbers and use that as an excuse to get even MORE free money thanks to the taxpayers.
And yeah, 150+ year copyrights is NOTHING but free money from the taxpayers, because it is taxpayers that are having to shell out for movies and music that should have been public domain decades ago. Instead we have congress critters blatantly taking treasonous bribes (BTW did you know there are SIX health care lobbyists for every congress critter ATM? How bad do you think the health care "reform" is gonna screw us with THAT level of bribery going on?) and passing ever more draconian laws.
So steal it, don't steal it, it really doesn't matter as these companies have now been infected with the "too big to fail" mentality. It is the mindset where you are entitled to ever rising profits, no matter the economy or how shitty their product is, and if the don't get those ever rising profits? Well then you are a dirty thief and they'll just bribe the government to take that money from you. So while you idea of protest is nice in theory, in practice it just gives them another bullet point on their PPT they show the congress critters they are bribing about how profits are down so it MUST be pirates. After all their shit never stinks and they are "too big to fail" so it HAS to be anyone other than their own incompetence, didn't you know that?