There are not many non-Americans foolish enough to fly United. The only people I know who do are US work colleagues who are building up their status (same applies to major chain hotels such as Marriott and Hilton). I tend to use SouthWest or Alaskan or Virgin America for US Domestic if I can. Meanwhile over here in Europe I've given up trying to get status and choose a reliable/safe airline on a preferred route over points any day.