There is the exclusives thing, but I think it goes the other way. The consoles are loss-leaders, meaning they're manufactured at a loss, then they make their money on game sales. So they need game sales to make up the numbers.

Yes, people buy playstations for the exclusives, because they know there will be many. Also I guess once you buy it you may need to justify the expense with more game purchases.

Now Sony is the publisher, so they get money either way. It may be that the cut is apportioned differently for PS sales, maybe the PS division needs to protect their numbers, but I know games companies in the past have talked about their reluctance to release on PC because of piracy, and the attitude seems to me to be that PC users need to be taught a lesson.

Personally I think the whole walled garden ecosystem is bullshit and in an ideal world we'd all be running open source software on open source hardware, and the only new hardware you'd get would be for performance upgrades, or because you wanted a handheld or a second machine. There wouldn't be this situation where people buy three separate machines just because some people decided their proprietary games would only work on their proprietary machines. It's absurdly wasteful.