The two main reasons: (a) It's still not finished, but mostly (b) all I ever see is people in love with how clever they can be with the language.
I don't need to see hyper-clever ways of using built-in lazy memoised lists to generate a Fibonacci sequence in a dozen keystrokes. If I get tempted over to Perl6 (or any other language) it'll be be by examples of how easy it makes the boring, mundane tasks that I actually need a langauge for - things like reading from/writing to files; handling dates/times nicely; etc. etc.
What I like about Perl5 is its "Make the easy things easy and the hard things possible" mantra. The only mantra I hear from Perl6 is "Look how cleverly you can solve this contrived example". That's not something I care about in the slightest when I think about what language to write my next program in.