IMO, much of the struggles in recent years can be chalked up to two factors: First, we had lots of players leave earlier than expected, which created year-to-year transitional discontinuity. Imagine having Ennis and / or Grant in 2015, or McCullough for 2016, or Malachi for 2017. Or Lydon last year. In no way do I begrudge their decision to leave, I'm just suggesting that we might not have been in this seeming cycle of perpetually starting over every year if things had worked out a bit differently if one or more of those players had decided to stick around a little bit longer.
Second, we couldn't build any depth due to the NCAA penalties / scholarship restrictions. This has been discussed a lot, no need to delve further into things here. But suffice it to say, being down 4 or 3 scholarships -- ~25% of a normal roster, really hurt.