Anybody who thinks Elon Musk doesn't make mistakes should read a few pages into
this thread. Long time members of this forum -- people who have spent years waiting for their Signature Model X -- are cancelling their Model X reservations because Elon and the Tesla design team
guessed wrong.
So it does happen. The S was a huge hit out of the ball park. The X has some really (REALLY!) cool bells and whistles, but functionally it was a bit of a miss for some prospective buyers. The 3 could go either way. I have great faith in Elon and Tesla to create another winner, but they won't please everybody. Just like the designs some people post here in the Model 3 forums. There are designs some think would be awesome, while other are saying, "Please, God, no!"
Back on subject, though, I would be amazed and shocked if the 3 didn't have free supercharging for all drivers. The fact is that daily use of a SC when you don't have to just isn't convenient. I don't have SC enabled and I'm fine with it. I'd rather get home, step out of the car, and spend all of 10 seconds plugging it in. I don't want to sit at a SC for 20 or 30 minutes just to save two bucks in electricity then drive home and plug it in anyway. Totally not worth it.
Tesla knows this. They expect some to need SC's if they live in an apartment and can't charge any other way, some to abuse their use of SC's just to pinch pennies, but most people will just want to get home and plug in and relax. The SC network will be there for everyone should they need it, but most people won't get a lot of use out of it. It's just not worth the time -- especially if it's cold, raining, snowing, etc. Also, if the SC's aren't in the relative path of the commute, people aren't going to take the extra time to drive to a SC when they don't need to just so they can sit there and wait.
Tesla takes all this into account and they'll include supercharging in the price so they can say every Tesla sold can be driven free for life.
Major selling point for them. Those who don't use it will help defray the costs of those who do.