I think I want to be sure I understand this.
If, netto, we have substantial more developers at the end of 4.7, we made the
correct choice. I beleive we should count our success mostly in the
"currency" Developers. I do not care about amount of users, per se, to me
they are but a factor to get more developers.
We should take the word "developer" with a grain of salt, though. Anyone
contributing to the development of Drupal is a developer in this case.