For better or worse, the relevant authorities in the US already have very well-established processes for figuring out what kinds of institutions (and even what specific graduate programs) "count" for different kinds of student visas, and so I would imagine that for this new visa category they would build on that existing foundation. Your fake-PhD business would need to deal with accreditation etc., and then compliance and overhead issues thereof- and that is A Whole Thing (ask me how I know).