I see this all or nothing argument when discussing new stuff. Same thing was said about passenger cars and quoted as one of the main reasons EVs would never catch on. It looks like a chicken and egg problem until you look at it less idealistically and more pragmatically. If you watch the presentation (and I hope everyone commenting here did that first), it's most likely that the charging infra is part of the package fleet operators buy. They showed battery+solar backed Megachargers that the fleet operators are likely to be using for the near term. With this in mind, those companies that are currently buying these trucks in high numbers, are also definitely buying the charging infra with it. So with this context in mind, charging infra isn't a problem right now. And just like Superchargers for passenger cars, they will only ever increase in numbers.
Slow charging is only a temporary problem and as evolution of Superchargers has made quote evident to date.
From my understanding of US laws and human biology, no one can drive 2000 miles non-stop without taking multiple breaks in tens of minutes each. In fact, Tesla Semi's range is 500 miles because it's right at the edge of how long a driver can safely drive non-stop and right before they are legally required to take a break, during which time they can charge the truck.