Irving is a lazy player for the most part. The reason why i say that is because he can literally get to the rim and finish AT WILL, against ANYONE. Yet, he decides to take contested 3's that he never comes close to making. It's just lazy basketball.
That isn't quite what's happening, actually.
Kyrie is actually shooting at a pretty good percentage on contested
shots. He has shot 39.2% on threes that are "tightly" covered (defender between 2 and 4 ft away) and 30% on "very tight" (defender within 2 ft). The latter is a very small sample of just 10 shots all season, but 30% is actually good on that kind of shot. And his 39.2% on tightly contested shots (which are his largest sample) is actually very good. Most player's efficiency tanks with defenders that close.
Where Kyrie is underperforming is, like a lot of our roster, on "wide open" threes. That is, on shots that have no defender within 6 ft and definitely NOT "contested". On those shots, Kyrie is shooting just 34.1%. That's well-below league average (~40%) for wide-open threes.
Unfortunately, Kyrie is not alone. Only Jayson (46.8%), Yabusele (45.5%), Horford (44.9%) and Jaylen (40.0%) are shooting league-average or above on wide-open threes. The rest of the roster are all shooting 36.1% or lower on what should be a much higher-percentage shot.
This is very much counter to what is 'normal'. Most players tend to shoot much, MUCH better on wide-open threes. Hence the league average is so much higher on that shot than on threes with tighter coverage. But other than for the 4 guys I mentioned, not so for the Celtics!
Our bizarre underperformance on these shots (which our offense has actually been very good at generating) and our paucity of attempts at the rim (and poor finishing at the rim) are the two glaring reasons our offense is so bad.
As a team, we rank near the bottom of the league in efficiency at these two shot types.