Good thing you missed the time when cables with DB9/DB25 connectors were everywhere, for every purpose.
Every USB-C cable that is not USB 2.0 (meaning 5gpbs and up) will be able to drive 4K@60Hz.
Of course, it's better now with Thunderbolt 4 where every Thunderbolt 4 cable is also an honest to god USB4 cable, and it's not as confusing for the consumer.
That's not different than USB-A. You can have charging-only, USB 2, USB 3, etc. cables. We had this for decades.
The USB-C connector was an opportunity to fix it: mandate all ports and all cables be full-spec. No "up to" non-sense.
And they squandered their chance.
I'd guess 'cost'.
A USB-C cable that can do the bare minimum needs five wires (one twisted pair for data, power, ground, and the configuration channel), and they can all be thin. A cable that can do everything adds to that four more differential pairs (which also have more stringent signal integrity requirements than the lone USB 2.0 pair), one extra pair for sideband use, and the power and ground wires must be thicker to handle the higher current. So it's tripled the number of wires, made some of them thicker, and the cable has to meet a more strict signal integrity. No wonder it's more expensive.
Why can’t all USB C cables just do all the things? To me, the fact that I can plug a cable into my graphics card… and it fits… and then it does nothing… that’s awful physical UX.