"Useful and usable" Perl 6 release coming in April

And the fact that KDE 4 represents a "latest and greatest" release which effectively meant KDE 3 would virtually end receiving attention from developers.
But perl 6 (at least in te early years) will not deprecate perl 5 at once, in will first just be an alternative language. Once perl 5 runs natively on parrot and performs adequately there is a chance of faster "deprecation" of perl 5 because the border between perl 5 and perl 6 will be fading (and people requiring more and better will probably start shifting towards perl 6).

But until that time I foresee that too many people/companies have too much depending on perl 5 that nobody will keep on supporting it. And that is the main difference with KDE, here nobody really has hard dependencies on KDE 3, just on a working desktop environment and applications that (still) work.