IME 20tb drives are easy to find.
I don't think the clouds have access to bigger drives or anything.
Similarly, we can buy 8x A100s, they're just fundamentally expensive whether you're a business or not.
There doesn't seem to be any "wall" up like there used to be with proprietary hardware.
For me these prices are prohibitive. Just like the A100s are (though those are even more so of course).
The problem is the common consumer relying on the cloud so these kind of products become niches and lose volume. Also, the cloud providers don't pay what we do for a GPU or HDD. They buy them by the ten thousands and get deep discounts. That's why the RRPs which we do pay are highly inflated.
Homelab vendor in Austin, TX with periodic sales, limited volume: https://shop.digitalspaceport.com
And they do have better sales.