That's... not as insurmountable as it seems.Edit: There are technical challenges too. One of the reasons making superchargers so fantastic is that we just plug in. The charger know who is charging and where to send the bill. This is because our Teslas sends an unique ID to the charger. Other EVs lack this. Which is part of the reason why using other chargers is so cumbersome with apps, rfid-dongles and expensive to run payment stations.
First, Teslas don't, to my knowledge, send any ID to the charger. They just have a flag telling the charger whether they're authorized to charge, and the car then communicates the billing info for that charge session back to the mothership. (This is actually really insecure...)
Second, CCS does support the vehicle sending a unique ID to the charger, the VIN, and some charging networks actually use this to provide plug-and-charge, and I think all CCS vehicles support this. (A different, and potentially worse, potential security vulnerability exists here, as VIN spoofing may be possible.)
Third, CCS also has a (probably actually secure, but also incredibly over-engineered) mechanism using asymmetric cryptography and TLS (that is, the same tech used for HTTPS). Not all CCS vehicles support this, though.
Of course, both CCS authentication methods mean that a Tesla Supercharger install would need a data connection to the mothership that it isn't required to have to bill non-Teslas (because of the car's connection to the mothership being used instead).