Technically there was nothing stopping the use of CCS2 in the US, as the L2 and L3 pins would simply not be used at people's homes. But one-phase J1772 was already around, and it was decided to go with legacy compatibility.
I'm sure CCS2 exists in more commercial settings with heavy duty EVs, e.g., Volvo Trucks:
CCS1 = SAE J1772 + DC.
J1772 has L1, L2/neutral, ground, control pins:
* https://en.wikipedia.org/wiki/SAE_J1772
J1772 is popular where one-phase is popular in residences (i.e., US, CA). CCS2 has L1, L2, L3, and neutral+ground:
* https://en.wikipedia.org/wiki/Type_2_connector
* https://en.wikipedia.org/wiki/SAE_J3068
Technically there was nothing stopping the use of CCS2 in the US, as the L2 and L3 pins would simply not be used at people's homes. But one-phase J1772 was already around, and it was decided to go with legacy compatibility.
I'm sure CCS2 exists in more commercial settings with heavy duty EVs, e.g., Volvo Trucks:
* https://www.volvotrucks.us/news-and-stories/press-releases/2...
Though high/er capacity (DC) plugs are being worked on:
* https://insideevs.com/news/535918/megawatt-charging-system-e...
* https://en.wikipedia.org/wiki/Megawatt_Charging_System