While I'm sure you already realize a boycott of one person isn't going to affect the demand curve at all, there are interesting implications to your position.
PC games like MW2 are clearly not perfectly competitive, however in general the cost to supply a good affects the decision to sell that item while the demand for the good dictates the price of the item. You wouldn't suggest that I should sell you a diamond for the $3 it cost me to extract it from a mine, and similarly differences in cost of production only translate to differences in price over the long run as competition drives out profit.
An organized boycott on the PC platform would lower demand and thus succeed in dramatically lowering prices for PC software. The consequence of this, however, would be more developers making the decision not to supply at the lower prices. The flip side is that if developers can release PC games at the same price and earn $10 more profit you will see much more attention paid to the platform and higher quality games released.
I agree with most of everything your saying, and I'm not boycotting Activision so much as $60 PC game releases. Also, i'm a capitalist so I agree with your premise. It is supply and demand, and obviously even at $60 demand was high. However, just because that is the case doesn't mean I should roll over and just go with the masses. I don't feel left out because I skipped this game.
Your diamond example makes your point, but this is more about price elasticity. Games are expensive to make, no one can argue that, but I believe those many of the costs that are associated with them are self induced and not always necessary. This is the reason why someone can make a movie for $20 million and it be a better movie than one with a $150 million budget. I don't believe in the premise that charging more will get you a better product. The console market as skewed development practices to the point where they don't focus on product sustainment...they just want to sell tons of units in bursts, then go on to the next product. Multiplatform is the way to go in order to maximize burst profit potential, and the price increase only fortifies the premise because it inflates profits on the front end, knowing that they are just going to lower the price down the road.
I don't believe we will ever see a shortage of PC games at the standard $50 price point, since there are plenty of smaller budget companies churning them out. The idea that somehow a company can't make a good game with a reasonable budget is ridiculous, since developers do it all the time. If we support the $60 increase we are only inviting ourselves to be taken advantage of. I shouldn't have to pay a $10 welfare payment on every game in order to bribe companies to develop for PC.
Thats my .02 but all are welcome.