Anybody is free to make an application to be a merit source, but one thing is involved here, one has to be more considerate in checking self to see if he's eligible enough for an application, check to see if you're worthy for the application and personally accessed yourself, Theymos can review those who applied at anytime when he feels there's a need to add more additional merit sources, here it's not in additional merit sources that matters if not the pattern through which tye merit sources distributes theirs, i want to believe that's how he has wanted his own, meanwhile the thread is still subjected to change in rules if he wish.
In all the merit source applications I have witnessed in this forum, I haven't seen where theymos approved any. It could be that he believed that the number of merit sources in BTT is sufficient for effective distribution of merits in the forum.
I also believe that without applications, theymos should be able to know active participants in the forum and give them the role of a merit source. I will not want to see new merit source application when old ones have not been attended to.