Not worth the capex to do that. Air cooling with evaporators up front is pretty standard and works great, not to mention fewer moving parts.

99% of data centers do not have liquid available to the rack. Liquid within the rack doesn't really help.

I don’t think there’s a GPU component so it’s probably a much lower power profile. Also, per this cloudflare write up the Turin gen of the AMD Epycs is very efficient: https://blog.cloudflare.com/gen13-launch/

Interop standards for this like Open19 are not widely deployed and without interoperability it’s a dead end since you need the hosting provider to give you the drop to your rack or cage. Hyperscalers I don’t know, but I’d guess they don’t deploy rack density that calls for liquid cooling yet.