

From my understanding, Valve would need to be hundreds of times more wealthy to be able to even consider manufacturing their own DRAM.
Edit: notably, this article seems to suggest that after significant government investmemt and with an already well-established knowledge and IP base, a fab costs around $15 billion dollars and optimisticly, a decade of construction. Given that Valve is starting from scratch, the price will be much higher. Chinese companies, backed by the Chinese government and using significant amounts of corporate espionage, have been trying to achive this for about 20 years, and are only just starting to catch up, nonetheless one (relatively) small software company.
Just accidentlly hit post, and the immediate delete took too long to federate.