But even if Xanterra doesn't fully open, there are still lots of parks that don't use them. Two of my nearby fed parks are closed to cars. So, you have to walk or bike in.
It will be interesting, as Utah is gradually opening right now. Zion, Bryce, and Canyonlands are rumored to be opening May 1 with limited facilities. Zion is the only one that has more than limited anyways, but the international tourism is out of the game.