There's an argument there, but Galecki (Leonard) is actually top-billed on Big Bang Theory, and Galecki/Parsons/Cuoco are apparently all paid the same.

I'm not sure if I agree with your conclusion about Americans wanting comedies with clear leads.  The top comedy, ratings-wise, on TV right now is Big Bang Theory, and it has only increased in both ratings and quality as it has evolved towards more of an ensemble show.  Modern Family is likewise very much an ensemble.

1.  Doing an uptown transfer for these sorts of shows (especially those with pre-opening buzz) isn't all that uncommon.  Indeed, the currently reigning Best Musical, Once, opened off-Broadway in December for a limited run and transferred in February (still running, too).  Indeed, set pictures suggest that's where this…