If you look at a any of the nvidia DGX boards it's already pretty close.

PCIe is a standard/commodity so that multiple vendors can compete and customers can save money. But at 8.0 speeds I'm not sure how many vendors will really be supplying, there's already only a few doing serdes this fast...

There are companies that specialize in memory controller ip that every one else uses, including large semi companies like Intel.

The ip companies are the first to support new standards, make their money selling to intel etc. Allowing intel or whomever to take their time to build higher performance ip.

These days you can buy any standard as a soft IP from Synopsys or Cadence. They take their previous serdes and modify it to meet the new standard. They have thousands of employees across the globe just doing that.

Isnt it about latency as well with DGX boards? Vs PCI-E. You can only fit so much RAM on a board that will realistically be plugging into a slot

Has the DGX actually shipped anywhere yet?