It seems to me that the point being made is that if a Corvette is going 5
miles
an hour, and a bike is also going exactly 5 miles an hour... One will not
be
"faster" than the other. Now, if you floor the pedal on that Corvette,
obviously its going to ditch the bike. But with everything being equal,
they
perform the same.

If a cheap amp is putting out a real 100 watts, and an expensive amp is
putting
out the same 100 watts, the differences won't be audible. At least, thats
how
I am understanding this whole debate.

That's correct. And we're also assuming that neither amp is being driven
into clipping when trying to attain that 100 watts.