Same thing hurts Utah, since they lose a bunch of CCGs and 2 rose bowls.
As to Washington St, they've been slightly better than BYU over the last decade, so it would be expected that they'd have better viewership. But the gap is larger than can be accounted for just by team success.
In the case of BYU though, I do think there's some obvious other arguments for lack of viewership/national interest.
The biggest being the lack of meaningful stakes - BYU plays bigger name opponents than most G5s...but even schools like Cincy or UCF have the advantage of their conference games meaning something, which tends to push their viewership above BYU.
So combine that with the lack of P5 affiliation and BYU has a lot of negatives as far as viewership