It's difficult on the back end of the charger as well.
A shopping centre or rest stop can't just spring for a few high capacity chargers for the car park. A single megawatt charger is 50 houses worth of consumption, so they now need a substation upgrade to provide what is basically a whole neighbourhood-equivalent of power.
Inertia, mostly.
Of course Plex then takes advantage of that with the slow erosion of the free edition.