There's a problem when your console is identified with third party games - MGS, FF are two that come to mind. You're angry that SE has "betrayed" Sony because they want more money? Why not point some blame at Sony, instead, for selling so few consoles? In that case, they wouldn't have to worry about FF13 not doing as well as it could (were the userbase larger).
Let's wind the clock back a few years - to the SNES days, when all games were on Nintendo systems. Yes, that includes FF1, 2, 3, 4, 5, and 6! Square then went to Sony's side, for a number of reasons. Notice how FF has jumped ship before? It will do so again, if there's more money to be made. If Sony doesn't do well, do you expect all third parties to follow them to the grave out of loyalty? You should be happy FF13 is still arriving on the PS3, FF7 (or any future FF) didn't even make it back to Nintendo systems. To those that think, "Oh, but PS3 will rise above all in time!!" These people have their money on the line, they have much more to lose than hopeful fanboys.
It seems you're placing all the "blame" out to Microsoft & SE, acting as if Sony was the helpless victim here. The truth is, this is business, not charity. SE was counting on Sony to perform better than they did (selling like the Wii), so they put themselves in this position. The moment DQ9 was announced to hit the DS, Sony should have been aware of the possibility of this happening. Third parties have more loyalty to money than to anything else - perhaps this is a lesson to be learned, mainly to Sony fans (since they had the leading console since PS1) - companies didn't stick on the Playstations because they were in love with Sony, but rather, the large userbase that came with it.
I understand you think SE is in a great position, doing so well and they don't need the money. However, that isn't the case - dev costs have been rising, and as their constant FF remakes have shown (even a Chrono Trigger port to DS), they're desperate for cash. The rise of the DS / Wii is also something different they may not quite understand. Milking DQ and FF will not keep them alive forever, so they need any help they can get.
Anyway, the whole thing isn't as big a deal as you make it out to be - the PS3 hasn't been selling that great, so these things will naturally happen. Even if the quality of the game takes a hit, I doubt it would be noticable. It's also unreasonable to think that even if Sony's console isn't the leader, it will still have a monopoly on all the games. Just ask the Ninty fans - the SNES > N64 losses were much worse, imo. Hell, even when the Wii is dominant SE still doesn't take it seriously. On the bright side - Sony is still getting FF13, and versus is still exclusive. If you want my opinion though, it's better not to stick so closely to one company, as it doesn't do you any good. It looks to me like you're thinking Sony is this flawless being, but honestly, they're just another company. It may be true that MS has made it their job to hurt Sony, but Sony's entrance didn't exactly help Nintendo, either. In the end, it benefits gamers when companies have to fight like this for our money.
@Pristine: haha, if Miyamoto could be bought, I imagine somebody would have taken him away long ago 
