I just find it Bizarre that Haas are the only American team and they never really made a big deal of it at all (and now make more of a deal about russia...). It's the equivalent of when we had Tim Howard and didn't tour USA after his world cup. Just odd PR from the start.
I guess it's because it's a sport that Americans don't care about a huge amount. The last American to win a GP was Andretti in the 70's. There is some interest there but it's not going to become dominant over NASCAR or IndyCar. Motorsports in the US is also quite far behind other sports there in popularity. Couple that with the fact Haas are never going to realistically compete and there isn't an American driver it's a bit of a non-starter.
I imagine the only way F1 would get big boost in the US is if an American team came in with serious cash to compete (be it a Ford, Chevrolet constructor/Red Bull sponsor equivalent) or an American equivalent of Verstappen turned up, who could potentially go on to dominate the sport.
When we had Howard (and Donovan) we obviously picked up new fans in the US. But we were never going to become a big team at that point and those players were never going to be seen as the best in the World. So support largely stays with Man U, Chelsea, Barca, Real etc.