(1) Are meat diets really any more diverse? If you 1-1 substituted chicken for quorn, beef for soy, etc., that seems basically the same to me.

(2) If cultivated meat becomes affordable, it's actually made of meat. The same stuff, just from a vat rather than a body.

This can easily be much more diverse, because suddenly all the endangered species, a few extinct species, and human flesh(!) legally get on the menu.