You've retreated from "buy one humanoid robot and it can make as many more as you want from scratch, it's like asking a genie for free wishes" to "there could be a regulatory framework that would require the manufacturers of humanoid robots to make a retail parts pipeline that allows your humanoid robot to build another humanoid robot at a cost lower than what the manufacturer would sell one for."

You didn't talk about the cost, but what's the point of having your robot assemble parts that the manufacturer will sell to you, assembled, at a lower price? It only makes sense if it's cheaper.