You are making assumptions and seem to be suggesting that Tesla’s supercharger pricing is not reflective of what they actually pay to operate and maintain supercharging sites. A commercial EV charging station would seem to be the very definition of an outlier given the data you’ve provided. I posted an actual commercial tariff upthread from PGE in California for reference.
Depends on usage. At $28 per kilowatt, the 350 kVA cabinet input for four stalls means a maximum average of just 87.5 kVA per stall. Assuming a 1.0 power factor (guessing here), that's a maximum of $2,450 per stall in demand cost per month. If you assume an average of 50% occupancy over 12 hours, delivering an average of 2 kWh per minute, that's 21,600 kWh per month, or an 8.8 cent demand fee, assuming there's no battery or solar input at all.
Of course, for superchargers that have lower utilization or that are mostly utilized only during commute hours, that number will be way higher. Of course, the batteries and solar input should push the number back down.
On the flip side, it also means that the higher the rates that they charge, the fewer people will use the superchargers, and the more each user will cost. The best thing for Tesla to do would be to charge higher costs during hours when lots of people need the chargers, and deeply discount the cost during other parts of the day/week, so that the demand costs get amortized over a larger number of vehicles.
A tiny fraction of Tesla’s supercharger stations have battery storage deployed. Ironically, there are more Tesla batteries deployed at Electrify America stations than Tesla stations.
All the stations I've paid attention to in California have battery storage, but that's admittedly a small percentage of the total number of stations.