USB4 is supposed to have proper labels: https://www.pcworld.com/article/2602229/better-usb-labels-ar...

I don't know if that necessarily helps though, because I've seen USB3 cables that seemingly have the bandwidth and power capabilities, but won't do video.

Capabilities are printed on the side of ethernet cables and the text printed on the cable rarely seems related to the actual capabilities of the ethernet plug. Some cat5e cables are rated for 1000mbps but will happily run 5000mbps or 2500mbps (because those standards came after the text on the cable was last updated), other "cat6" cables are scams and struggle achieving gigabit speeds without packet loss.

Plus, it doesn't really matter if you put "e-marker 100W USB3 2x2 20gbps" on a cable when half those features depend on compatibility from both sides of the plug (notably, supposedly high-end devices not supporting 2x2 mode or DP Alt mode or charging/drawing more than 60W of power).

We used to what ? Back in the day there are countless cables with no printing. Sometime the only way to know if they are 3.0 or not if checking if they have blue connector.

That would only confuse potential buyers. You have to design everyday products for non-technical people.