There's no guarantee in the 1st Round either - Fowler, Bud Dupree, Shaq Thompson, Shaq Lawson, Leonard Floyd, Jarvis Jones, Dee Ford, etc have all been "busts" despite taken in the 1st Round. Outside of Khalil Mack and Vic Beasley (both selected in the Top 10) - every pass rusher drafted in the 1st Round in the last 4 years has been a bust. And in reality, besides those 2, EVERY pass rusher drafted in all rounds of the last 4 years has been a bust (so far).....Labeling a player a bust after 1 or 2 years is premature as I think a couple of those names above can have a decent NFL career - it takes time to develop to be a productive player in the NFL. Part of the reason it's so hard to find pass rushers is because almost all of them played their entire college career going against college Tackles that aren't good enough to be back-ups in the NFL. Only 1 Tackle from the SEC will get drafted in the 1st 3 rounds this year (Cam) and he projects more of a Guard at the NFL level.
Fowler was essentially a rookie this year as he missed last season with a torn ACL, Dupree was good this year and coming on before missing time with injury, Shaq Thompson is used as a Will in a 4-3, Floyd as a rookie notched 7 sacks, Lawson is a rookie and played in 8 games due to injury, Dee ford had 10 sacks behind Tamba Hali and Justin Houston. I'm confused by your argument. You labeled these guys busts, but you said it's premature.