To people comparing sales and sales only to determine whether something has made profit or not:
Profit is not determined by sales. It is determined by factoring in three things:
1) How much did it bring in as revenue
2) How much did it cost to make (+marketing costs)
3) What better project could have been assigned to the same team.
Platinum Games is not one to get on a Sonic title, obviously, so 3) is not a factor in Bayonetta's case. Also, Bayonetta costs a fraction of what a game like the current AAA+ games cost, and still had an insanely high quality.
Also, sooner or later, big studios and companies will need to act like TV broadcasters, keeping some of the critically acclaimed shows for prestige, even if the money is barely coming back. It is good for pleasing your "viewers"/players.