Probably because it’s extremely affordable to train the smaller models.
If I had the gumption (and a data set) I could afford to spend a few hundred bucks to fine tune a model for shits and giggles and I’m just a Random Internet Dude.
I’m all for it, Any Day Now™ I have this idea I want to try and having these people do all this optimization work will probably make it affordable to attempt given I don’t actually know what I’m doing so there will be a whole lot of “yeah, that doesn’t work” going on.