Increasing the version is a straightforward way to say “n is outdated, use n+1.” As a publisher I don’t want to start a new project with zero followers, especially if the project does the same exact thing my previous project did, just better.
Yeah, that's a good point and a lot of API interface churn we're seeing in the ecosystem makes sense to me now. People don't want to lose their social clout.
One could argue that that is exactly what happened in 2008, when the "sister language" meme was introduced. At that time, the Perl Porters basically abandoned all support for Perl 6 and started developing on Perl 5 again.
So development of Perl 6 basically fell back on just a handful of people, on the Parrot backend, which became less and less acceptable for Perl 6. And then people still wonder why it took so long?