There was good commentary by a former NBA player who said Bud is great at making journeyman NBA players better. He's not really known for developing young talent. Maybe our bench coaches can do that. Perhaps Bud is panicking he is going to lose his job and wants to go down with the ship by playing veterans.
That's the problem though- in every scenario, including Bud panicking, Dunn is the best move possible. They lack defense, athleticism, and heart. Dun has those three things, and he is a competent player on offense as well. No matter the scenario, Dunn would help.
Best case scenario for Bud is to sneak into the playoffs, where Suns will face a certain sweep. That's not going to save his job, if his job is in jeopardy. Durant is most likely going to be traded in the offseason, the Suns will get some assets, but not nearly as much as they've wasted, they are still going to be in cap hell, though they might sneak under the second apron for a hot minute. Your best bet is to develop what little cheap, young talent you have (Dunn, Oso, Bol, Gillespie) and hope that one of them ends up being a starter-level player and a couple others develop into bench contributors. Dunn is already, by far your best defender, best athlete, and has a bigger heart than anyone currently in the rotation. He is not great on offense, but he is competent.
Similar issue at PG. Jones and Morris are not coming back. You have no picks and no heart. Play Collin Gillespie and hope he ends up being a decent player. He is not a great defender, but he is better than Jones, he has great court vision, very good shoot, and he plays hard.