Looking at the current Yakuza numbers - I bet on PS it would be at least in the top 10, unlike the current top 20.
Not everything can be bought with money. Like Zune or Windows Phone. Just money is not enough.
Except it can. If MS continues to put out titles that appeal to a fan base then the fans will adopt it.
Let me ask you something. If MS bought Square would fans of Final Fantasy stop buying Final Fantasy games ? Or would they pick pc or xbox to play those games ?
You picked two things that have nothing to do with this.
Zune is a product MS made from the ground up that had no existing fan base and apple had over 80% of the market.
Windows phone was a new product in a market that both andriod and ios had over whelming market share.
For both products it required constant investment from MS.
IF MS bought Square (since i used it as an example already) they would be buying already established money making games with fans who will follow the franchise because they did so before (nintendo to sony). So whatever they lay out in the purchase will eventually be made up by MS through sales of the established games