If the team was open to any drivers available, who would people think are more likely to get the seats? The Europeans, South Americans & Asians or the North Americans?
The talent is there from all 4 regions, but would it make more sense for the team to pick up drivers who already have experience such as test drivers for current teams and possibly-unemployed drivers (e.g. Button/Barrichello/Sato) or to pick up an all-American team experienced in IndyCars/Champ cars?
I would have said it would make more sense to pick up 2 drivers from either current teams or go talent searching in GP2 or Formula Nippon then use an American driver as a test driver or as a 2nd driver to give them some experience before fielding a full-on American team with little or no experience of F1 or its circuits.
I would much rather have a few experienced open-wheeled Americans get behind the wheel of a 2010-spec car and start running it now. Even a makeshift car will allow driver development and the engineering development to start asap. But, History has taught us all how usefull previous open-wheeled series skills are in an F1 car. So, USF1 needs them to be racing an F1 car now.