Historically, only the absolute blue bloods had the quality depth to field consistently good teams. College football teams, in general, had weak spots due to attrition, injury etc. With the portal, teams now have the option to try and fill those voids to field a team that's more solid overall. Teams that do this successfully will benefit.
That said, teams that overdo it, as noted above, may run into chemistry and/or recruiting issues. It's like taking Afrin....works great for a couple days, but if you overdo it, you become dependent upon it.
Iowa, it seems, has run into a figurative glass ceiling. Our recruiting is better than it has been in the past, but we've gotten to a point where we're consistently losing players early to the NFL. We don't have the depth to absorb those losses and it's hurting us. Throw in some unexpected injuries or departures and we can get into depth issues very quickly. This, I think, is what we're seeing with the offensive line.
The receivers is a similar confluence of events, but for different reasons. We lost two starters to transfer because, I think, our offense is not a viable showcase for receiver talent. Players of NFL caliber don't really get a chance to shine in our offense. I'd look elsewhere two in that situation. Then...holy crap the injuries. It's reminiscent of the RB issues back in the 00's. ISU should be grateful that we got wiped out at WR. As bad as SP is, I don't think we lose that game if we had the receiver crew it looked like we'd have back in May. I have to think losing two WR's to Purdon't has to be a wake up call for KF.