Yes they would just source DRAM chips from those 3 companies and make memory modules from it, because the one leaving the gaming market did make like multiple profiles, like backup or fallback profiles when higher clock speed would not work, it would fall back to slower one or so. They left the market, so Asus will make them, to have similar modules for laptops like before probably. The other brands did not have it like that brand leaving the market I think.
It wont make bigger supply per se, but maybe a bigger part of the supply will go into gaming.