Probably because you have to be able to crimp that connector as simple as possible, without too much tooling OR training needed.
You literally can train anyone, as non-tech as possible, to crimp 8 wires with a $5 tool in 5-10 minutes.
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We have gone from giant USB-A to the slim USB-C and converters are available. We have mini Display Port and converters are available. Why has no one tried to miniaturize RJ45?
You literally can train anyone, as non-tech as possible, to crimp 8 wires with a $5 tool in 5-10 minutes.
The last time before that was when I was working as an IT tech in high school 20 years ago.
But yeah - I'm not even sure if "normal" people know you can make your own cables.