Is there an aftermarket for OEM 21” wheels and tires?

If my wife were to purchase an Equinox EV equipped with 21” wheels and tires, and we were to want to install 19” or even 18” as replacements, could we pay for the replacements by selling the 21”ers to EqEVers who would appreciate them at 1/2 to 2/3 the price at the dealer?