They (GF) do not make DRAM. They might have an eDRAM process inherited from IBM, but it would not be competitive.
You’re correct that DRAM is a very specialized process. The bit cell capacitors are a trench type that is uncommon in the general industry, so the major logic fabs would have a fairly uphill battle to become competitive (they also have no desire to enter the DRAM market in general).
You’re correct that DRAM is a very specialized process. The bit cell capacitors are a trench type that is uncommon in the general industry, so the major logic fabs would have a fairly uphill battle to become competitive (they also have no desire to enter the DRAM market in general).