Two things. First, it was stated very clearly from day one that the purpose of Perl 6 was to break backward compatibility in all the ways it needed breaking, so you should not be at all surprised ten years later that we're breaking backward compatibility.
Second, it is my belief (which may take twenty or thirty years to falsify but could be truified rather faster) that for every manager that does not use Perl 6 because it is not Perl 5, there will (eventually) be N managers who will use Perl 6 because it is not Perl 5, for some N greater than unity. If I didn't believe that, I wouldn't have spent the last decade pouring my heart and soul into it.
As for whether Perl 5 and Perl 6 are different languages, that's kinda silly; every new version of Perl is a different language. The only question is how different, and the answer to that is never 0% or 100%. On this, as on most issues, I am a flaming moderate, and do not appreciate arguments that ignore one half of the truth or the other. I'd rather see the whole truth.
And the other half of this truth is that people who have actually programmed in Perl 6 tend to report that it still feels very much like Perl on some fundamental level, regardless of the various syntax and semantic tweaks we've made. So it really depends on the meaning of that fuzzy term "Perl". As a linguist, I'm quite content to let definitions be fuzzy like that. :-)