I'm completely in sync with you on this:
I really enjoy developing in Perl -- the language is fun and the CPAN library is terrific, but the real crown jewel is the community -- that's priceless
However, GUIs are important, and Perl is not good at that. The only GUI library Perl really has good bindings with, and comes preinstalled with most distributions is Tk. But Tk is very limited, especially in the "looks & feel" department.
I wish I could use Perl for everything I do, but unfortunately I can't. My "losing momentum" claim is that thinks are unlikely to improve from now on, because the focus of most enthusiastic language tweakers is not on Perl any more.