I won't say, "I don't think it has," because it demonstrably has not.
The language has been released in open beta. It still has many properties that I think chase away those who approach it outside of language research communities. As a Perl 5 nostalgia fix, the learning curve is just too daunting, so as the beta progresses, I expect it to continue to build its own base of enthusiasts, the same way Perl did when it was first released.
So the language has not "flopped" yet because it hasn't had a chance to succeed yet.
It took Perl many years to go from a small toy that a trivial number of Usenet enthusiasts had heard of to a standard part of the Unix and Unix-like toolset. I don't think Perl 6 will gain traction any faster, especially given the learning curve. That's not flopping.
However, it has some substantial advantages over other languages. High on that list is the trivial nature of slinging highly functional grammars as first-class objects. That's something that you just can't do as easily in any other language that I know of. Perl 5 parsers and those of many other high level languages have some pretty severe performance penalties; yacc and its kin aren't dynamic enough; the various parser generators for Java are fast and mostly complete, but really painful to use.
Basically, you need a language that closely integrates grammars with the language itself in order gain the benefits of Perl 6. Here's and example parser I posted to reddit the other day:
A few other notable things that I think will draw people in:
The generalization of operators over iterable sequences and the hyper-operator version of reduction are features that you're going to hear a lot more about, I suspect. Perhaps in Perl 6, perhaps in other languages that adopt these ideas. I'm especially stunned by the utility of hyper-method-invocation (foo>>.method) which dispatches a given method over any iterable sequence of objects (whether they are the same type or not).
Full macros have not yet landed, not least because we've never had a full understanding of what macros would be. We know that they need to operate on the ASTs that represent code, and all of the self-hosting properties necessary to support that are there, but the exact syntax and semantics that are most Perl-friendly haven't fully gelled, yet. Once they do, I think that every language to have true macros in the past (mostly Lisp variants) has demonstrated the power of this tool.
A few other languages auto-generate accessors for classes, but I find the way Perl 6 does it to be a substantial improvement on the field, and it really is a joy to use. I think others will feel the same.
Speaking of objects, role composition will take some time for people to get used to, but as in other languages that have had similar features, I think this will be critical to Perl 6's adoption.
There are dozens of smaller features that are just quality-of-life benefits ranging from lexical variable/named parameter passing to the way any block can be turned into an anonymous closure and even curried. Some of these will be important to some, but not to others. It will be interesting to see it play out.