Let's look at the facts. Here are the 13 players that left early after last season:
Sheriden Lawley - out of football
Chris Britton - out of football
Anthony Watkins - playing at Wagner
Brice McAllister - playing at UMass
Dan Oak - out of football
Bryan Coney - playing at University of New Haven
Chris Jean-Pierre - out of football ?
Ja'Kevious Vickers - playing at Butler JC
Braydon Brown - playing at Lackawanna College
Brad Westmark - out of football
Nick Zecchino - out of football?
Aaron Garland - out of football
John Robinson IV - playing at Tennessee St.
So, we have 7 out of football, 2 playing at JC, 2 playing FCS, 1 playing FBS, and 1 playing Division 2.
Out of these 13, 5 were on the Holy Cross 2 deep. Of those 5, 3 are out of football, 1 is playing FBS, and 1 is playing FCS.
Based on reports at the time, UConn did want Brown to stay. Out of all of the players listed above that are still playing football, I would think Brown and McAllister could have helped this year, but that wouldn't have made or broke this team.
As for your Cobb analogy, Cobb was always recognized as a talented basketball player. He was a 4*/3* recruit with offers from Alabama, Arkansas, BC, Kansas St., Old Dominion, Seton Hall, George Mason, Miss. St., South Carolina, Washington, VCU. The only thing missing for Cobb was motivation and development. I don't think the players listed above had the same athletic ability as Cobb or the same motivation and development issues.