Tesla's chargers will still support the Tesla protocol as well as CCS. They do that right now to support older Teslas. Everything else charging on a Tesla charger will talk CCS, just like they've been doing in Europe for a long time.
No other chargers will support Tesla's protocol. They'll all be CCS.
If I understand correctly, this means that Tesla vehicles that do not have CCS retrofit will not work with J3400 NACS third party chargers. Is that correct?
When you said "these chargers," do you mean the V3 Superchargers with CCS+J3400? Or, do you mean NACS 3rd party charging stations?