USB 3.0/3.1/3.2 Gen 1 aka the kind that can do 5 gbps can only use cables up to 3m in length. Meanwhile Ethernet uses a similar twisted pair copper cable, but can do 10 gbps over 100m.
What gives, why is USB so limited in terms of cable length?
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USB 3.2 can do 20GBit/s with a USB-C connecote.
USB is designed to be cheap and does not use a lot of power. So the electronics used to integrate the signal are not that complex, the result is you can handle lots of distortion.
Compare taht to a 10Gbit/s ethernet card where the cheapest is at $30 you can compare that to 1Gbit/s cads that start at $14. https://www.newegg.com/p/pl?N=100158104%20600013864%204814&Order=1
Take a look at them too, the heatsinks are not there for looks, you would not add them if they as not needed. If you search for the power usage e you find info like https://edgeoptic.com/products/network-interface-cards/10g-nic-x550-2t/ where a car uses max 13W at 10Gbit/s This is because you need quite a complex signal processing to filter and interpreter the signal.
Compare that to power usage for USB tranciver like https://www.ti.com/lit/ds/symlink/tusb1310.pdf look at page 31 where the sun of all the power pins is 0.43W
A computer typically have multiple USB port so less then 1W each is a lot better than over 10
You do not what to add that all devices that use USB at high speed. The ability for long-range is not really worth the drawback when it is intended for usage on a desktop
They take a look at the cable. Here is a correction of a CAT6 cable https://commons.wikimedia.org/wiki/File:Cross_section_of_a_Cat6_patch_cable.jpg the plastic separator is to keep the cable away from each other. The wires are thicker too.
So you could cant make them as thin and flexible as USB cables, Remember USB-C has 24 wires for multiple purposes, not just 8.
So USB can get away with thinner, more flexible, and cheaper cables
If you really need long-range USB there are USB extenders that use ethernet cables so you can put another device 100 meters away
So USB is designed to provide high speed at a short distance at low cost, low power usage, and thin flexible wires. If you would build it to work at 100m the cost, power usage, and wire size all would increase.
Engineering is about compromises and the important design parameter for USB is not the same as for Ethernet.
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