USF1 can't be thrown out of the F1WC arbitrarily. They haven't committed any infractions to warrant that, yet. The line-up of teams can't be switched around on whims. There are agreements and contracts involved.
The cause for the USF1 failure to produce a car is most likely some combination of lack of money and poor management. It doesn't help that the majority of Americans couldn't care less about it. Hell, the majority of Americans aren't even aware an American team exists or even what Formula 1 is.
sad but true.