The barriers are the US demands that nobody should sell semiconductor manufacturing equipment to China.

Otherwise their memory manufacturing companies would be happy to exploit this opportunity.

Actually some Chinese companies already sell cheap DDR5 memory modules, but their production capacity is severely limited by the US blockade, so the cheap memories are available in few places, mainly in Asia.

So the high memory prices are caused by USA both by the AI companies that have bought most of the existing production and by the US government, who has sabotaged the Chinese memory vendors since a couple of years ago, in order to protect the market share of Micron (the US sanctions coincided with the moment when several companies, including Apple, intended to use the cheaper Chinese memories, so preventing this to happen seems a much more likely reason for the "sanctions" than the BS excuse that consumer DDR DIMMs and SSDs are dual-use products that may benefit the military. Even if that were true, the US sanctions did not prevent at all the Chinese from producing anything that would be needed in a small quantity, like for a military application. The sanctions have prevented only the mass production of devices using state-of-the-art lithography, which would have impacted the prices in consumer markets).