You could easily make alot of money fabbing parts for mopars, that’s a no brainer(people know you know your shit). The thing is you actually have to do it and not talk about it. It should be illegal to charge 400 for a simple intake, but like you said it’s supply and demand.
My buddy who makes springs, intakes, etc. For jeeps makes money because he is in business to. He doesn’t feel bad about charging alot of money when people will pay. Hence the reason why he lives in million+ dollar house and has about 6 cars.