You can get an enterprise 7.68TB drive for $530: https://www.amazon.com/SOLIDIGM-D5-P5430-Solid-State-Drive/dp/B0C96FTCS3

It’s a little more than 4x2TB but you get enterprise reliability.

And considering AMD has roughly double the number of cores per CPU as Intel, AMD probably has a much higher share of CPU cores and of revenue than the 20-ish % market share in sockets sold.

I’m not saying anything about prices, just about available capacities.

Doubt it. 64TB SSDs are already here in a 2.5"-ish form factor (U.2/u.3/E3.S). 128TB are only a couple years out.

40TB HDDs will be competing with 2.5" 128TB SSDs.