There was an writeup a while ago in "Seeking Alpha" that Tesla will ultimately make more money on the SuperCharger network than building actual cars. The idea is, they will license the technology to other auto manufacturers for a "one time fee" per vehicle they build, thus will generate much larger returns as hundreds of thousands of cars are built to use the SC network. Those guys in Fremont are no dummies, this is part of their master plan, licensing is far more lucrative than building iron.. Yes, the SC network needs to be built out and maintained, but it won't be used as often as everyone thinks, as most charging is done at home. The SA article came out with an actual price per SC use, and factored earlier uses as "more valuable" than later uses because a certain percentage of cars would be totaled etc.
SA article "Supercharging TSLA":
SuperCharging Tesla - Seeking Alpha
Edit: what other manufacturers will use the SC network? How about all of them as Teslas technology becomes the defacto standard within 5 years, and their nationwide network has already been deployed? It's far less expensive to license this from Tesla than install your own network.