Bucks get off one of NBA's worst contracts, turning Khris Middleton into Andrew Wiggans, a backup PG and SF depth. Also gets a 19ppg 11 boards center to pair with Bobby Portis and Giannis replacing the one year left with Lopez. Wiggans gives them back some of the defense they lost when Jrue left, but also have 3&D wing T Craig for additional versatility.
Golden State sends off Andrew Wiggans, whom they've been trying to offload for ahwile, and turn him into a real center in Brook Lopez who stretches the floor and gives them a real chance at competing this year. They do all of this without giving up any young players.
Knicks really just facilitate the trade by trading immediate picks for future picks. The reality is, nobody they draft in the next two years will play a large role in their ability to compete right now, and they don't have available roster spots for the picks they have. This pushes their picks down the road for future moves or a rebuild more towards when their window may start to close in 5 years or so. Chicago likely shuts the whole thing down if the picks aren't helping them in the super-near future.
Bulls take on another bad, hard-to-move contract, but they get picks in next years draft to help with their current rebuild. They may have to ride out the remaining vets on the team, but at least they'll be active in the drafts.