What is it with fabs where there is just no competition springing up outside the existing memory cartels? Is the knowledge of how to build and run a fab strictly controlled by these companies? Is all qualified talent just immediately poached and put behind NDA and noncompetes? It just makes no sense. Capitalism would suggest these conditions with so much unstable equilibrium in this market would see increase in supply to take advantage of the pricing. The fact that this isn't playing out as such suggests there are some very powerful thumbs on the scale of this "free" market.
It takes about a decade to bring one up and during EVERY wave of a booming memory demand supply crunch there has been a subsequent round of major bankruptcies from suppliers who decided to scale and had no demand when they finally got online.
Supply is not elastic and responds very much slower than demand. There's no conspiracy or corruption needed for this result.