But unfortunately they went to shit soon after G&C left, sinking even lower into 80s crap than Sparks did. And their peak was only like 4 and a half albums unlike Sparks' decade-long peak period. But yeah 10cc at their peak is tremendous, their debut album is nearly perfect to me.

"the three or four most important keyboard-based meta-pop bands"

What's your list here? Sparks, 10cc, and who else? The Buggles maybe?