I'm very happy for these player's hard work paying off for them and it certainly helps with recruiting, but I think it is a valid point that all these accolades haven't produced more wins for Iowa football. Individual achievement will always be secondary to team achievement. I think it's interesting how well Kittle has played in the NFL, something we rarely saw at Iowa. His two touchdown performance at Ohio State displayed his enormous potential which never was really seen again. The three tight end set was basically, "retired". There's an old story repeated in N. Carolina which basically says that the only person to successfully stop Michal Jordan from scoring was Dean Smith. I think Iowa suffers from this as well.
Kittle's production at Iowa (or relative lack-thereof compared to current NFL production) was largely situational.
In his first year playing (2013 as RS freshman), he began to get some PT at the end of the season. He played in 3 games total, including as a 3rd TE vs. Ohio State, a game in which he recorded 1 reception. That is his only career reception vs. Ohio State, and the only game he ever played against them. I believe you are thinking of Jake Duzey, who had 6 for 138 and 1 TD in that game.
In his second season on the field, he played in the first 3 games, and then not a snap after. I assume he dealt with injuries.
In his 3rd season he broke out. He had 20 receptions for 290 yards and 6 TDs for the 2015 Hawkeyes. You could argue that he could have been used more heavily, but he was on a team that featured Matt Vandenberg (NFL potential before repeated foot injuries), Tevaun Smith (played in NFL), Henry Krieger Coble (played in NFL), Leshun Daniels (played in NFL), and Akrum Wadley and Jordan Canzieri (2 of the most productive backs of the KF-era). Kittle was tied for 4th on the team in receptions with Canzieri (behind MVB, Smith, and HKC). That was also a Greg Davis offense that used TEs differently than KOK or BF.
In his 4th season he struggled with injuries again. He had 22 receptions for 314 yards and 4 TDs, but he only played in 9 games. He missed the 1st game of the season, and he was pretty hobbled for the entire second half.