Particularly in the Northeast, where the NBE has all of a sudden given kids from the DMV to New England another option to the OBE teams that left.
When the ACC raided the OBE, it was thought that the schools known for their FB or MBB would take that success with them.
However, that oddly hasn't happened in either sport.
One factor that doesn't get discussed enough is the reimagined NBE, which has siphoned off talent in strongholds like New York, when it was believed (by Swofford) that he'd be killing off his competition (particularly in what he believed at the time was the ACC's signature sport).
The Old Big East was (at one time) the unquestioned best conference in college basketball. It's hard to fault Swofford for thinking he'd gobble up that status. Nevertheless, the ACC is currently the 6th best conference. The Big 12 is by and large the best college basketball conference now (and likely to remain with the expansion).
Can the ACC reverse this decade long trend - especially now that Duke and UNC no longer have their great coaches? I kinda think the ACC will hover around that 5-6 area, and the NBE will be a factor in keeping them there (given the overlap in the footprint).
Did the ACC grow too big? I believe the ACC (and similarly CUSA from the G5) has suffered by growing the roster too much. That said, you can't discount the existence of the NBE conference that slid into the void created when the OBE teams defected.
Kenpom ratings since 2014: