The superchargers are presently an untapped revenue source. Nearly all Model S and Model X owners connect to these at no cost. This leads to a negative cash flow for Tesla, but it has great potential. Imagine a gas car manufacturer also selling the gas to their customers. This pass ends with the advent of the Model 3, where using a Supercharger will cost money, localized to electric costs, with some profit built in. The question is then, how much saturation will it take, of Model 3s nationally, before the Supercharger cash flow is reversed into a positive direction? But of course, one is not required to charge exclusively at a Supercharger, and a high percentage of all charging will be done at home. But road trips will likely require a trip to the local Supercharger. I know I have already looked at common vacation spots that I take for weekend camping or longer trips to see locations of Superchargers to test the viability of taking the Model 3 over my gas powered vehicle. I think likely, assuming most Model 3 owners do not use them for their main charger, that the number needed to turn Superchargers profitable will be well over 100k, maybe even a number verging on the total number of reservations (~300k-500k).