You'd think it would be the opposite

You said:

"To my eyes, ND has two separate issues: lack of blue chip WRs and (probably related to the first issue) the inability to involve blue chip WRs in the offense."

I agree we have both issues, but I would think, all else equal, the two issues would be inversely related.

If you have a dearth of 4 and 5 star talent at a particular position, it would be easier, not harder, to get the blue chip talent you do have involved in the offense.

I can see why it might be difficult for Saban to involve Thaiu Jones-Bell, Javon Baker and Traeshon Holden involved when DaVonta Smith, John Metchie, Jaylen Waddle and Slade Bolden are all getting dozens of catches and hundreds of yards. It is tougher to understand why Kelly couldn't involve Jordan Johnson more when Javon McKinley, Ben Skowronek (a grad transfer) and Avery Davis (a converted QB turned RB/WR turned DB turned WR again) were the leading WRs -- and everyone else in the top 7 is either a TE or RB.