Or you can put it otherwise: If Google can't afford to ask artists to do something for free, then who can? (Meaning that there will always be enough 'good enough' fan bois that they don't need the high profile artists.)

Google can afford to pay for them. That's the reason the artists are pissed.

It's like a millionaire asking a homeless bum for change, claiming that the "exposure" of being a nice guy will earn the bum a few more donations.