Comment by bluGill
The is true today. However EVs are becoming more common and chargers are being built. In a few years chargers will be more common and have to compete on price. Today Tesla can get away with charging more to some customers - those people will figure it out though and eventually they will have enough options that they can go elsewhere. It is hard enough to brand gasoline (you can have a brand specific additive package most don't but they do exist) electrons are even more identical.
Tesla has enough time to get brand recognition for cheap charging, even if it gets less relevant over time.
Even when chargers become more common in cities, there will always be some places like smaller villages or long roads where you only have one option; that option possibly being a Tesla charger.
So even if it loses significance, the difference will still be there. And maybe it will be sufficient to retain Tesla being known for being cheaper long-term (because of charging).
Whether that's realistic: I don't know.