Good point, I didn't realise Perl6 was in a similar situation. However it seems that adoption of Perl6 is very low, so I suspect Perl5 isn't going to get killed off any time soon.
Very little new stuff is being developed in Perl, period. I don't know anyone working in Perl who is not maintaining existing codebases. I haven't heard Perl proposed for anything new in over a decade. That further reduces the motivation to move to Perl 6.
It depends what you're using it for. Certainly it wouldn't make sense to use it for web stuff. However I use perl exclusively for server-side "shell" scripting, and it excels at that. More powerful than bash, less compatibility worries than python (I've had issues even between 2.* versions). If I have perl5.* on a server my scripts work everywhere. I regularly start new server-side scripting projects using perl, including a recent webpage-to-video conversion batch script. To be honest there is no other platform that I would even consider using for this kind of thing. Is there even anything that comes close to perl's cross-platform, rapid development, stability and general compatibility?
That's because of binary API changes, and only affects Perl modules with C parts in them. Source compatibility has been preserved at least across the entire 5.x line.