If you really think that by asking money and shutting up
Perl, you would make it more popular and profitable, then
I challenge you to go out and try to do it.
If you read the licensing terms, you can take Perl, take
advantage of the artistic license, rename it slightly, and
make your own version which can be proprietary if you want.
(See oraperl and sybperl for examples where this was done
with Perl 4.)
My prediction based on both theory and observation of past
examples (particularly examples of what people in the Lisp
world do wrong time after time again) is that you will put
in a lot of energy, lose money, and never achieve
popularity. For some of the theory, the usually referred
to starting place is
Cathedral and the Bazaar.
Of course if you want to charge money for something and
can get away with it, go ahead. No less than Larry Wall
has said that, It's almost like we're doing Windows users
a favor by charging them money for something they could get
for free, because they get confused otherwise. But I
think that as time goes by it is becoming more mainstream
to accept that it is possible for software to be both free
and good at the same time.