I think most programs have attrition along the way so that there are more underclassmen than upper-, but we have a real ton of Fr and So on this year's roster. If you're in that cohort and don't see the door opening, then you take a look elsewhere.

From the official roster of 122 players (not sure which proportion are on scholarships) https://byucougars.com/sports/football/roster?sort=class_level

We have:
51 Fr (38 Fr, 13 Redshirt Fr)
26 So (8 So, 18RS So)
24 Jr (5 Jr, 19 RS Jr)
22 Sr (11 Sr, 10 RS Sr)

Note, we'll see how well we compete next year with some departing contributors, but it looks like we will have a similar number of goodbyes for the next few years. But that current crop of Freshmen — and I know it will get blurred a bit with missions and redshirts — looks like a bumper crop of experience as they become upperclassmen.