I don't know exactly what the situation is with other local boards, but on the Croatian local board we had a situation for a long time where we had a lot of quality posts but few merit sources.
I also noticed, this happened on my local Indonesian board. Indonesian local board has several merit source (3 users or more) but the merit statistics are not much when compared to some other local board which have a number of active users that is not much different from the Indonesian local board. Some of the reasons I know of is the quality of posts that may not meet the standards expected by merit sources or other users, this affects the number of merits distributed there each month.
This situation seems to have been discussed often enough that @AakZaki and @skarais who are two of our local users submitted their applications so far. If there is an additional merit source on local boards, then I believe we can see a lot of users getting motivated to make quality posts especially for low ranking users.
Merit Source Aplication - AakZakiskarais - Merit Source Aplication