For EV cars I think we are at the point where long trips are pretty easily do-able along the Interstates, my 70 something parents did a 5K mile road trip this summer in their VW ID.4 using mostly Electrify America for DC fast charging. They only got stuck on a slow charger in Lubbock on the way back. And if they would have heeded my advice not to go through Lubbock, it would not have happened.
For the Tesla semi, I think we're a long way off from replacing diesel owner-operators for long haul. How many mega chargers we gonna need? Don't know the answer but it's way more than we have. What I think will happen is that regional operators that want to use these will build their own charging infrastructure.
Auto EV travel is pretty much a snap.
I dont forsee EV semis ever replacing long haul trucking, but as you say for regional/ in town deliveries and known point to point transfer they will be successful.
It's easy to construct a scenario where they wont work, and just as easy to construct routes that will.
Forget about Tesla - Volvo, Benz, Freightliner, Peterbuit, Kenworth, Scania arent dumping tons of money into this market blindly.