The problem is that you need to have $10+B to throw at the problem after you license patents from the incumbents, and even then you'll end up being behind them technologically by the time your fab is up and running, so your marginal costs won't be appreciably better than contracting with the existing manufacturers for their more advanced memory.
You could theoretically spend several times more than that to try to get ahead over the course of two or three generations, but for that kind of money you could just as easily secure some very preferential pricing from one or more of the incumbents, thereby ensuring that everyone else trying to put a lot of RAM into a PC has to pay more.
The most viable path to establishing a new leading-edge competitor in this space is for a government to throw lots of money at the problem, knowing that it'll be years at best before it produces anything competitive, but having the advantage of being able to more or less ignore IP issues and having a potential demand far higher than any one memory customer can produce on its own. China is doing this for the NAND market, too.
You could theoretically spend several times more than that to try to get ahead over the course of two or three generations, but for that kind of money you could just as easily secure some very preferential pricing from one or more of the incumbents, thereby ensuring that everyone else trying to put a lot of RAM into a PC has to pay more.
The most viable path to establishing a new leading-edge competitor in this space is for a government to throw lots of money at the problem, knowing that it'll be years at best before it produces anything competitive, but having the advantage of being able to more or less ignore IP issues and having a potential demand far higher than any one memory customer can produce on its own. China is doing this for the NAND market, too.