I imagine they made that choice with the intention of preventing others from wrestling control from the devs with a libre fork at the early stages of developmen

I imagine they made that choice with the intention of preventing others from wrestling control from the devs with a libre fork at the early stages of development when they weren't sure just how much money they would make through Patreon. The release cycle favors Patreon subscribers by a week or two. As compatibility rounds out, this will be less of a draw. It's a little similar to how PJ64 did things for a while with their donor system, except AFAIK PJ64 is still closed source.