if anything, pricing will be around the same. Difference will be in availability.

I wonder so much what their initial capacity was (which ought to go up marginally, and what their expected capacity curves look like.

I would not expect them to dump cheap ram. That is a false hope. The world needs volume, massively more volume, and it feels like everyone else is going to take a sizable fraction of a decade to even start responding. Maybe perhaps possibly CXMT can scale fast, but they have many multiples to grow before they are more than a drop in the bucket.

It's also unclear when if they too will want to start stacking 12 then 16 then 24 rams atop each other, to sell chips that cost what multiples of what GPUs used to.

They won't, no one will. Too much investment for too much of a risk of the bubble popping and yet another run of the boom-bust cycle that left the world with not even a handful of RAM makers in the first place.