I would frankly say that “it all comes down to the actual economics of computer software.”   Software, once developed and put into service, remains in service for a very long time.   “Rewrites,” however earnestly the developer teams may long for them, are almost never economically justified:   the business risk is too high and the return-on-investment too low.

Therefore, the best overall strategy is to familiarize yourself with as many programming languages as you can.   Perl-6, yes, and Perl-5, and many, many more that aren’t Perl.   Because, throughout your career, you’re always going to be presented with a “more-or-less totally-new” situation, and you’re going to need to be able to “land four paws down.”   The broader (not necessarily “deeper”) your personal knowledge-base is, the more employable you will continue to be.   Probably none of the legacy-apps that you will be tasked to support, will be free of “maleficent odor.”

As you continue to explore new languages (and I happen to find that to be fun ...), the more you will see how much common-ground all of them have.   This perspective will take several years to develop.