As I understand it: because not enough people will use it through these ways, leading to not enough motivation for the dev(s?) .

but an order of magnitude smaller

I’m pretty sure that would be three orders of magnitude.

Most people’s ELOs don’t shift much after settling into your “natural” rank, which should happen after about 50 matches or so.

Ehm, 50 matches seems like a lot to me. Especially if they aren’t enjoyable (yet) because of flawed matchmaking.