I think it's all because of the perception of the entire room being transfers. There's something about "Ohio State doesn't have a single guy who was recruited by OSU!" and "none of the backups have been here longer than 18 months" that makes it seem much worse than other places even if the reality is (as you said) nobody in college really has a legitimate backup any more.
If Baldwin doesn't transfer, we wouldn't be hearing much about how bad the QB depth is. Even though the reality is the backup QB would be a redshirt freshman with zero collegiate snaps who was committed to a G5 school before OSU swept in late. Baldwin would have had a little more experience in Ohio State's system than Hoak, but I don't think anybody would have been super confident with calling OSU a national title contender if they'd had to throw Baldwin into the fire against Sparty or Penn State or TTUN with conference/national title hopes on the line.