Yeah, it may be a stretch.
Tesla needs pull throughs for towing anyway. It's a major pain to unhook a trailer to back into a Tesla stall. If you look at e.g. InyoKern, CA, there is a pull through big enough for a Semi with Trailer. It will block the Rivian pull through.
The cost of building a nation wide Semi only charging network that will only be used by 100,000 trucks is going to be gigantic, and basically cap ex sitting empty most of the time.
But if 2M Tesla vehicles can use those stations, they instantly expands the network for everyone, and starts generating revenue from day one. Of course, among major routes you will have locations with 50 Megawatt chargers for Semis, and small car chargers over at the next establishment. And of course there won't be huge chargers at the downtown Safeway.
But building out a new location, especially at an existing truck stop, they could continue to put more and larger pull throughs there. They put some V4 chargers in, and as they need more capacity, they add batteries and more V4 chargers. They are building sites like this already. Ready for another 40 stations, conduit in the ground, concrete pads built, but no hardware.
NACS has been tested to 900kW with "non-liquid cooled vehicle". The charge port likely is the limiting factor. NACS doesn't have a max on Amperage. If a Semi has a liquid cooled NACS port, it will be able to go higher, maybe 50%? That may be enough for "70% in 30 minutes"