Apple doesn't own any foundries, so no. It's not trivial to spin up a DRAM foundry either. I do wonder if we'll see TSMC enter the market though. Maybe under pressure from Apple or nvidia...

There are no large scale pure play DRAM fabs that I’m aware of, so Apple is (more or less) buying from the same 3 companies as everyone else.

Apple doesn't own semiconductor fabs. They're not capable of making their own RAM.