Why? Because there are, IIRC 7-8 different chargers and ports.
Some are cross-compatible, but most aren't.
So it costs the customer more money to buy adapters, and these things aren't cheap.
Some cars come with them, but you're still paying for them.
Then you have the charge station that can only accommodate one or two alternatives.
Hell, some charge stations are AC, and others DC.
It does need sorting out.
I used to have a Nissan Leaf 30KW accenta (old style). Best vehicle I ever drove, and I drove quite a few (also Class 1 for 10+ years, Scania, Mercedes, Iveco, Renault, Volvo, MAN, DAF, Foden, manual, auto, semi-auto, crash boxes. I drove them all).