Why?
Because either a new standard is not allowed. Or it is allowed, but then highly probably just one… and the central planning way. One standard/product is worked on, one is accepted as the successo.
No selection in the wild of the one that survives (depending of what we talk about, the survivor is sometimes the one that is technically better, sometimes it is the one that is cheaper, or faster in bandwith or latency or prettier, or …).
This sometimes work ok for 1-2 successors, but the more times pass by, the more central planing (or lack of free market) fails.
If one is very honest it has to see both sides of it.
Both has their pros and cons (not equally weighted though).
The regulated way has to be done as rarely as possible (very hard to decide when it is a good idea…)
Most of Europe already has a standard 230V plug (https://en.wikipedia.org/wiki/Schuko). It would probably be easier to get a unified 230V power plug than to change the USB-C port again after a decade.
“Until 1987, mains voltage in large parts of Europe, including Germany, Austria and Switzerland, was 220(±22)V while the UK used 240(±24)V. Standard ISO IEC 60038:1983 defined the new standard European voltage to be 230(±23)V.”
Amending laws takes much less time than eternity. Lawmakers are people, they can process information and make changes when appropriate. You can be sure that the industry will not forget to remind them when a change seems sensible.