@infection has talked about this... He kept bakkking da cakkkks so long that he painted himself in a corner and got to a point where he was forced to pivot. He could have swapped out other pieces along the way when we had clear needs and could find some balance but around 50 wins and playoff births gets him a new contract so why risk the biscuit until you have to. He had to see it and get copious amounts of data before making his moves... but then he becomes overly reactionary and overpays to get it done. He becomes too anchored to his deals and his players imo (see Exum, Dante and to a lesser extent Bradley, Tony). The fact he couldn't let Quin move Conley to the bench this season when that is clearly what Quin decided to do further cements the idea to me that he likes to stick with things until he's proved wrong or right.
Call it patience or stubborness or being risk averse or whatever you like. The rotating band aids at point guard has been a problem... the fact he overpaid for Mike makes it worse.