It is likely that merit system has made significant impacts on account farmers. Something like they stop attention to make new alt-accounts.
Furthermore, several account farms have been detected and got punishments from moderators. This is another good impact of merit sytem in terms of cleaning the forum a bit.
Decreasing on the newly created users by 36% after merit's implementation within 100 days is very significant.
It is just a theory, but you maybe right.
We can say that merit system is really reducing the multiple accounts of people or spammers and focusing many members on creating a good quality post.