Is Mugen trying to create demand for this car? Every hobby store is out of stock or backordered for this car.

yes

like every company they don't have all kits under production at once, they cycle them around between all their kits. the R is a popular kit & has sold out in the states, you can get them from over seas if you want one desperately. i don't think they realised how much of a hit it was going to be.