With a Tesla it’s only 20 minutes to get 80% charge. It would be more than sufficient to do the LA to SF drive. I’d imagine most people would want to stop at least that long during the drive just to stretch their legs.
I have heard stories and seen pictures of people waiting to charge in California, but I have never personally waited for a supercharger on my many road trips. The infrastructure needs to be built out to keep pace with EV adoption, but my understanding is the california problem is more about how long it takes to get building permits in the state than any lack of desire to add chargers.
As for poor routing, the fastest chargers are rarely more than a few hundred meters from major routes. A couple times they have been more convenient than gas stations. The only charger I've been to that was more than 2-3 lights away from the highway is Owen Sound, Ontario, but that city is known as a travel black hole and doesn't have a ring road or fast way through.
I know my routes are niche (which is why the traffic is on the other road), but for me it just didn’t make sense yet.
Your use case is quite interesting. Got an example?
The lack of waypoints in the Tesla navigation is their biggest missing piece of software currently. The navigation is extremely good about recalculating both the directions and charge plan as as you go even if you deviate from the suggested route. I sometimes cheat a little by navigating to a midway point. For example, I set Orangeville as the destination leaving Kitchener-Waterloo for Sudbury since I didn’t feel like going through Toronto.
The worst detour I've experienced in recent years was a serious accident in the middle-of-nowhere Utah, which closed the highway in both directions for almost 24 hours. The shortest paved detour around the accident added 150km of nothingness to the trip.