#1 - Don't overvalue someone that isn't making your team win - Atlanta Hawks (2017-present)
For the Atlanta Hawks, the seeds of their transition from a 60-win team that made the Eastern Conference Finals to a bottomed-out one took a few seasons. The 2014-15 team was the pinnacle of a Hawks era that started in 2007 when Al Horford was a rookie.
The 60-win season was followed by a 48-win one, and then Al Horford was allowed to walk to the Celtics in the summer of 2016. Mediocrity was on the doorstep at that point and provided a 43-win season in 2016-17, after which they fired Mike Budenholzer and moved headlong into the rebuilding process.
Trae Young was acquired after a 24-win season in 2017-18 via a draft-day trade with Dallas for Luka Doncic, and the Hawks quickly made him their cornerstone to go with 2nd year forward John Collins. In retrospect, Doncic is the far superior player, but that's another argument for another day.
Over the next few years, the Hawks went 29-53 and 20-47, adding Clint Capela, Bogan Bogdanovic, De'Andre Hunter, Kevin Huerter, and Danilo Gallinari to help spur their breakout in 2020-21 with a 41-31 record and a surprising trip to the Eastern Conference Finals.
After the follow-up campaign in 2021-22 resulted in a 43-39 disappointment and a 1st round exit, the Hawks went big in a deal to bring young star DeJounte Murray to the ATL, in hopes that he would pair with Trae Young for an All-Star backcourt (and help shore up their perimeter defense).
However, they went 41-41 in 2022-23 in another backsliding year, appearing farther away from the contending team they wanted to be.
This season, Atlanta is 12-18 and on the verge of falling short of the Play-In Tournament, not to mention out of playoff position. This is not where they want to be. Their rebuild was never complete. The Eastern Conference Finals berth tricked them into thinking they had arrived when it was more likely a fluke.
Atlanta has changed coaches, players, and everything else around Trae Young trying to recapture that lightning-in-a-bottle moment from 2021. The next move might be to move their star, as they are currently on pace for a 32-50 record which makes them a likely candidate to blow up the roster once more.