The entire population of EV drivers in Glacier National Park is a small group of people.
The entire population of Tesla drivers in Glacier National Park is an even smaller group of people.
Having just returned from Glacier National Park, I'd have to disagree. We saw MANY Model 3's and Model Y's. The main road there ("Going to the Sun") is one long 50 mile narrow road with about a hundred turn off places. So there is essentially a long parade of cars going each direction. We had the opportunity see what everyone else was driving, and we saw plenty of Teslas.
The growing number of Teslas on the road may be sneaking up on you.
FWIW, this was a place where a BIG vehicle is a relative disadvantage. Almost no gas stations there as well, and I doubt they can safely get a tanker truck up the narrow road climbing to Logan Pass.
These facilities DO have electricity though, so a future world with mostly EVs would be able to refuel at the interior sections of the park, but not gas cars.