No. I dont believe that to be the case. In fact Ive seen it stated quite clearly on p5p that this was a misinterpretation of something Larry said once and that it has never been true. Perl 5.10 is going to be Perl5, theres no intention of making Perl 5.10 anything more than a better Perl5. Perl 5.10 may have some Perl6ish features, and it probably wont introduce any new features that directly contradict Perl6, but its Perl5.

What people are doing on Perl 5.9.x is to make a better, smaller, faster, more efficient, more convenient Perl5, which is actually in my mind a direct threat to the Perl6 project. The better Perl5 gets the higher the bar will be for Perl6. In fact I suspect that unless Perl6 represents serious advantages over Perl5 for the Perl5 feature set that Perl5 will never be replaced by Perl6. Instead I expect that what we will see is a bifurcation, with both continuing on to have long lives but for two mostly different user communities. (And IMO we are already seeing this bifurcation occur with Pugs).