https://en.wikipedia.org/wiki/Moore%27s_second_law: “Rock's law or Moore's second law, named for Arthur Rock or Gordon Moore, says that the cost of a semiconductor chip fabrication plant doubles every four years”

Wafer machines from the 1970s could be fairly cheap today, if there were sufficient demand for chips from the 1970s (~1MHz, no power states, 16 bit if you’re lucky, etc), but that trend would have to stop and reverse significantly for affordable wafer factories for modern hardware to be a thing.