Not sure anyone should be surprised that Tesla is raising Supercharger pricing.
In the beginning, with the original Roadster there was no supercharging. You charged at home or scrounged around for a welding company, a RV site or anyplace that you could get 240V.
Then the Model S was released and word was that an extra $2,000 was baked into the price to support charging at the new Supercharger stations.
When the Superchargers began to be a significant cost to Tesla they slowly weened owners off expecting free Superchargers for life. Car prices were moved down a bit and the FSC for life became a special item, only if you ordered by a certain date.
Then you were given a set amount of FSC to allow some long distance travel for free.
Then they instituted congestion charges for overstaying your charging time.
Then they eliminated FSC all together, except for people ordering within a certain time limit.
Then the FSC for life was eliminated and owners could no longer transfer their FSC for life to the next owner.
Now, only some early buyers are being Grandfathered in, but all the new buyers expect to pay for their Supercharging.
The pricing has always been a bit variable, but the trend is for the costs to go up.
Tesla has decided that the fairest thing, to the most people, is to reduce the vehicle pricing as low as profitably possible, and to charge those using the Superchargers a market price for the energy.
Destination chargers are similar. Each location can choose to charge for people pluging in, or often times offering it free as an inducemtent for gaining additional profitable patrons.
Just as the price of gas is different at each location, determined by profit and volume goals, as well as local taxes, operation costs and competitive pressures.
Owners will typically check out their charging options and choose the program that best serves their needs as far as cost, speed and convenience.
Final solution will be when most EVs are powered by Solar, charging will be rapid and convenient. Batteries will be used to modulate the peaks and valleys to make it most efficient.