It's funny that you call this an "very aggressive dumping strategy" while AI vendors are doing the same but with even greater losses and on a much larger scale.
It's all simply a fight for market share.
The original sin is the existing DRAM vendors selling their entire (spare) capacity to the likes of OpenAI.
No one sold their capacity to OpenAI. The vast majority of DRAM is transacted in what is essentially a quarterly auction.