Steel would be the way to go to keep the cost down. I think if they were steel versus machined billet you would sell waaay more sets. There's a lot of people that want 20s but cant necessarily afford a custom set of 20s, and if they could I don't think they would buy machined rally wheels. IMHO (Not trying to be an a$$hole im kind of right there with everyone else right now.) So I think as a selling standpoint, steel is what they need to be made out of.
Now the question is, what about beauty rings and center caps
That would be the bees knees!
I would buy a set in steel that's for sure.