Gobert started to close out on KD then realized he wasn't going to affect the shot. If KD had put the ball down and taken a couple steps inside then Gobert was gonna meet him there. You're right that Jrue could have gotten an open 18-footer if he wanted it, but his #'s from 18 feet are barely different than his #'s from 3pt and he was already 3-5 from 3pt on the day.
Where did you get those made-up numbers?
KD this season was 45% from 3pt and 48.7% on long mids. For his career he's 38% on 3pt and 44% on long mids. The difference is tiny, far less than the difference between winning and simply tying (as KD himself could tell you from recent experience).
Jrue this year was 39% from 3pt and 40% on long mids. For his career he's 36% from 3pt and 39.6% from long mids.
There's almost NO difference in their %'s and then you're gonna get 6 feet closer to the defense and give them an extra second to close out on you? All to take a shot that will only tie the game and not win it?