Non-Tesla fast charging stations also tend to be broken a lot, and are installed in small numbers, often single units. It's tough to plan a trip where you need a charge at a particular location when you could be screwed if a single spot is occupied or out of order. Most Tesla locations are 6 spots or more, and they're much better about fixing them when they break.
Yup, and the just added real-time status on the nav map so you can see how many slots are available and re-route if needed.
I regularly make a ~300mi roundtrip with our Tesla, I wouldn't own one today if that wasn't possible.
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Before anyone brings up ChaDeMo(I have the adapter), SAE combo neither are nearly as fast(120kW) in real-world use and have nearly as much market penetration.
The super-charger network is also something that's planned and built-out with the intention of being to make the major arterials rather than having a patchwork of various companies providing chargers.