From comments here and on Twitter, many are complaining that Tesla shouldn't open its supercharger to third party brands.
However, I originally thought that SC was always bound to open up at a certain point or would cease to exist once EV stations become common.
The reason is simple... scale. Right now, SC makes sense to be proprietary because Tesla needed that to push EV forward. We are already at a point where most legacy makers are pulling the trigger on the switch, however slow that is.
Thus, opening now is actually a great timing. It'd still make people to buy Tesla (no adapter needed. Just plug and go), and as more and more EVs start using SC, it makes financial sense for Tesla to invest into faster, bigger, and/or simply more SC locations. Because right now, there are already quite a few SC location that sit empty or never reached peak at any point in life. They aren't exactly cheap to put together either. At a suggested 170k per station, a 10 stall station is a million-dollar project each.
Imagine being the largest car maker and "gas" station operator in the world.