Cat 5 or 6 cannot be made on the same machinery as cat7 because cat7
uses individually shielded wires, twiisted together into a sheilded
cable. REALLY nasty stuff to work with. And 3 standards - cat7, cat7a
and cat7f.

OK. I was told that in the cat 5e era, with cat 6 coming online.

With electronics, sometimes items are truly different and sometimes they
are tested and selected for grade. If the construction is different,
they can't be the same obviously. If the components are selected for
grade, then often they sell "A" grade on the "B" grade line just to fill
orders. In the IC business, the procedure is known as "paint and remark".

Now if 7, 7a, and 7f use the same materials, then there is a chance at
some point they are the same quality.