This is incorrect. The CCS spec allows only a maximum of 200 amps. While there is talk about 170kW charging, that is with a 850V charging voltage, which no EV uses today (it is closer to 400V). Tesla superchargers routinely pull 370 amps. So Tesla can't trivially just use the existing standard.
As Matbl rightly points out Tesla are using bone stock Type-2 (but high quality) in current EU cars, and just playing fast and loose with DC-Mid (of which AFAIK Tesla are the only adopters) IMO.
The _only_ reason I can see for this is Tesla own liability on both the car and the charging.
In a "spec" based world everyone is covering their ass. So with variable quality fittings/cabling/connectors and liability for incident crosses organisational boundaries, the easiest way for standard bodies to defend against this is to build fat into the standards to allow for poor workmanship /materials via excess capacity to ensure "lowest bidder to spec" still leaves some room for sub-optimal performance. Effectively requiring something "overkill" if done to exact quality levels, but sufficient in sub optimal conditions.
Inevitably this leads to a response with the financial motivated trend is to just barely meet the minimum specs. (and specifically testing regime)
A good example would be the UK 13 pin plug.
Early examples (i.e. MK's from 25 years ago), when matched with an early 13A socket could deliver sustained 13A pretty much indefinitely. As time has moved on, manufacturers drive down costs, the quality has dropped significantly, but they still meet the testing regime. They can still deliver 13A, but basically only as long as the test regime states they must. Try and run one overnight at max capacity and it will melt around the fuse carrier as over time the thickness in those holders have been penny pinched away.... (btw one fix is to solder the fuse into the holder

)
This is why the UMC in the UK is capped at 10A when run on a 13A socket