There are three possible wiring modes in North American split-phase wiring:
- 120V only: One hot, neutral, and ground. (/2 plus ground)
- 240V only: one hot, the other hot, and ground, no neutral. (/2 plus ground)
- 240V/120V: both hots, and neutral, and ground. (/3 plus ground)
Note the same /2 cable is used in both of the first examples. Just the white wire is marked with tape to mark it as a "hot", and the wires are landed on a 240V breaker not a 120V. So if you are 100% confident that your future 240V chargers will be 240V-only, you could get away with /2 cable.
Unfortunately I am aware that some chargers are not. I don't know what's wrong with those builders, the bits they need 120V for could easily be made to work on 240V, and then the charger could be marketed worldwide. SMH...
But there's another way
You could bring out 6/3 cable out to a subpanel, giving you 240/120V split at the subpanel. Very standard stuff. Then, add a breaker and receptacle for whcihever charger you get, when you get it. The general idea is, you're only going to be charging one EV at a time. So if you have a 30A charger and a 50A charger, you only need to provision 50A of service, not 80A.
The same logic applies when bringing power out to a single RV parking/camp site. You can provision all of 240/50, 240/30, 120/30 and 120/20, knowing that an RV will only use one of them at a time.