That's not a bad thought. IMO, he's struggled for two reasons: he missed out on some high school guys and Oscar.
He's had a bunch of 'can't miss' HS guys that he's tried to force - Edwards, Livingston, Hopkins, Collins, Clarke, Askew, et cetera. For a guy who pushed one and done - hard - it hurt when the guys he had to lean on to be his best players weren't that good.
Secondarily, he had a black hole of a focal point in Oscar. The dude would put up video game numbers, but more out of the quantity of attempts and less out of the quality of shot/possession. When you throw it into the post, every possession, for a guy whose best offensive move is a put-back, it's not going to lead to a lot of 3PT shots. Kentucky was 351st and 330th for 3PA/FGA in the two years with Oscar.
All that said, Kentucky was the #1 3PT shooting team in the country last year...the first year without Oscar.
Lastly, he's still had three years in a row with top-20 offensive efficiency metrics. So, I'm a bit confused about how you are pointing to his offense, which is one of nine teams to be top-20 offensively the last three years. Of those nine, just five have been top-10 two or more times: Arizona, Kentucky, Gonzaga, Purdue, and Baylor. That feels like pretty good offensive company to be in.