USB 3 has 5 times the bandwidth of USB 2. The industry is in a state of flux. If you study it, you will see that that is so. You are entitled to your opinion, but my own results differ. Again, there is nothing wrong with my cables, with my current interfaces, or anything else. And again, I am a Jazz musician, and our music is much dense than pop, rap, etc.
Since you are so keen on USB 2, why don't you head on over to Sweetwater, and find the lowest latency USB 2 interface? Then compare it to the Focusrite Clarette TB interface ($600, i.e., reasonably priced).
I think your theory is fine, but the devices don't delver it. Maybe it's not practical to do so. In any event I don't believe that TB devices are a gimmick. Most of the top studios use them.
Let me know what you think.