What I’d like to see is something with thermals of the T7 Shield but with DRAM and USB 4 speed, but AFAIK, that does not exist.
OK, after making the mistake of buying a USB 3.2 Gen 2x2 SSD, I'll answer my own question on why you would buy your enclosures separately from the SSD. The consumer market SSD solutions aren't just a bit behind. They're way behind.
You had mentioned that this gap existed, but I didn't realize just how wide that gap was because I was looking at attractive looking 20Gbps drives without realizing that I wouldn't be able to use those drives to their full specification.
The gap between 20Gbps and TB4 is small enough to overlook in terms of actual usage for most people, but the gap between 10Gbps and TB4 is consequential. The equivalence in options that I was wrestling with was a mirage on one side of the equation.
The simplicity and price competitiveness of consumer market solutions completely vanish once you come to the realization that there's a lot of fine print and it's easy to make an expensive mistake that you can't fix.
I think we will eventually get back to a place where the tech matures and my assumptions about cost-benefit tilt back toward the consumer market solution, but that could be a while. In the meantime, I'll be watching for what TB5 solutions come onto the market with great interest.