Why don't Americans write big plays anymore?

Why don't Americans write big plays anymore?

I've written 8 big American plays -- which I define as plays that deal with public as well as private concerns and a cast that goes beyond a domestic circle, with subplots.  I've also written 4 modest-sized plays and 2 biggies set in England. Americans can't afford casts the size of Streetcar or Salesman-- the big cast social cross-section plays we get to see today mostly come from England, where they are pre-screened through success in a subsidized production.