Generally, Post-up is among the least productive possession types, similar to isolation. It's really just an isolation with your back to the basket, the end result best case being a contested shot while other play types seek unconstested shots.
Last year the entire league averaged between 0.74 points per possession to 1.01 ppp. The Bulls were 0.92 ppp.
Versus Spot Up Jump shots, the league was 0.92 to 1.12. The Bulls were 0.98.
Versus Transition, the league was 0.99 to 1.19. The Bulls were 1.08.
Versus Iso, the league was 0.76 to 1.06. The Bulls were 0.82.
Post up can still make sense if you have an very talented post up player, like James Harden who was 1.21 ppp or developing great post up player like Towns who was 1.02 ppp. Neither Lauri nor Wendell showed much promise in the post. Lauri was was 0.86 ppp and Wendell was 0.63.
We got a good view of how the two styles contrasted when Boylen hard switched from a post-up centric offense pre-Feb to a normal transition to jump shot offense in Feb.
In Jan, the Bulls offense was among the league worst at 27th.
In Feb, the Bulls were the 2nd best offensive in the league.
https://stats.nba.com/teams/advanced/?sort=OFF_RATING&dir=-1&Season=2018-19&SeasonType=Regular%20Season&Month=5The other "bonus" of transition/jump shot offense is that it's easier for bench & roleplayers to run. Bulls lost two preseason games because the other team with their scrubs ran a simple run-fast-and-jack-up-a-3. Every few possessions, that 3 will go in. The Bulls scrubs tried to run plays and basically failed 5, 6, 7 possessions in a row going on scoring droughts lasting almost a quarter.
Even Kris Dunn has a higher eFG% from 3 than he does inside the 3 point arc. There's nobody on this other than Lavine (and probably Gafford) that scores so well inside it warrants an offense that tries to go inside as a first option.
The other factor is our passing situation. Teams with talented passers like Rondo or Cp3 may have a good reason to feed the post or run lob plays for bigs. We don't have anyone even half as good as either passer. Some of our lob plays vs Milwaukee were cringe worthy, sailing out of bounds. If Gafford wasn't as talented a leaper as he was none of our lob attempts would have connected.
The team's strengths just don't seem to be posting up or passing.