I agree with you that Burks deserves a ton of credit for the success we had 20-21. Nor do I blame him for last year's disappointment. It was unfair to put him into the full-time PG role. Prior to that, he had some fantastic games coming up clutch (that 4th Q with 5 threes stands out in particular).
But I think he's just a necessary casualty to move the team forward. We don't have the veteran-led, > .500 team we thought we had this time last year. Randle took a big step back, Rose & Noel were missing in action, and Kemba was a lost gamble.
If we're going to grow, we've got to find minutes for our young guys and see what we've got. Push come to shove, Burks is just easier to move than Fournier. Grimes, Cam, even Deuce can start dipping into those minutes.
FO could still find a way to keep Kobe Burks and make it work, but moving on seems to be the most straightforward approach and fits the revised timeline.