IMHO, ambition is not publicity.
Setting high ambitions doesn't mean make big announcements like "make python 5x faster" without any evidence that the approach is promising.
OTOH the pypy guys, for example, have kept a much lower profile but much higher ambitions, like write a completely new compiler toolchain with a novel architecture and then implement python on top of it. I wouldn't say they didn't have "harder things to do".
