Plenty have not progressed.
They almost all progress, just some faster than others. But the ones who do quickly enough are the ones who stick around, and the ones we talk about. If they didn't progress as expected, they'd be stuck on RB2 or gone altogether. Jesse had as solid a track record of developing young guys as anyone. Muyl or DE getting longer sub appearances are not necessarily some major difference in philosophy as they are a matter of circumstance. Armas has done well in his short time in charge, but he hasn't shown anything special in that area, yet.