One point of evidence can be the BioPerl and BioPython communities. On github there are currently 111 stars and 57 forks for BioPerl while there are 350 stars and 179 forks for BioPython.
Fair point. I do suspect that this is in part due to a difference in user demographics.
People using BioPerl just use it to get something done and don't care to join the larger community. In Perl we call it the DarkPAN.
Meanwhile anyone wishing to use Python will at least have needed to make an effort to learn the language, since there is nothing else quite like it; and as such probably more likely to invest further effort.
BioPerl: https://github.com/bioperl/bioperl-live
BioPython: https://github.com/biopython/biopython