There are some ways to get this off the ground much quicker. One or more companies could buy an existing non-leading-edge fab like GlobalFoundaries. That buys a lot of expertise so you're not starting from zero.
DRAM also benefits from being very regular and relatively simple. It used to be what you bring up on a new process node to help prove things out.
It also isn't impossible to reduce reliance on ASML if you're willing to throw money at it. That's definitely a super-long-game move but it could be done.
I'm not going to argue that someone is going to do any of this but if demand is sustained it is possible.