Correct, it's true at many other positions where you carry multiple backups.  And it would be true at QB if we were keeping 3 (since the 3rd is your future developmental guy). But more and more teams are going with just 2 QB on the active roster and placing their young developmental QB on the practice squad.  Which is exactly what the Broncos are hoping to do here.

The starting QB, and even his backup, are just too important to throw in a small-college UDFA rookie that you didn't groom for that role throughout the offseason and training camp. Even the teams that draft a guy high in the draft for that purpose have to scramble to give those guys a crash course for that season.  You don't do that for someone intended to be a camp arm.  Remember that they drafted Chad Kelly too, who was supposed to be the developmental QB. Sloter was only here because Kelly was injured.

I loved what we saw from Kyle, and I hope he makes our practice squad. But he just wasn't groomed to play THIS season.