why would a rebuilding team offer Thomas a max contract?
This is a business. You want to attract fans. You want to sell merchandise. You want to win games. You sign him to field a decent product. You sign him to put asses in the seats. You sign him so that you can match your 2018 #1 shiny new draft pick with a guy who knows how to win in this league. You sign him so you have someone to put on all the posters and act as the face of the franchise while you go through a transition. You sign him because he can put up almost 30 points a game.
Why does this need to be explained? Or do you believe that the multi-year tanking scenario is the only way to get ahead in this league?
You also don't want to hamstring your team financially or stunt the development of young players. You don't want to win 10 more games but still not make the playoffs. What point does that serve?
And why would Thomas go to one of those rebuilding teams? If the only reason is they offered more money then everyone else, what message does that send those young players and why would you want the franchise to be in the hands of someone who is only about the money?
There are absolutely some teams where Thomas would be a good fit outside of staying in Cleveland (off the top of my head - Milwaukee, San Antonio, Houston (if Paul leaves), Denver, Detroit, the Clippers, and then New York and the Lakers for slightly different reasons). Those teams, by and large, just won't have cap space for a max contract. Now if certain teams take some unexpected jumps this year (not necessarily the playoffs but near them), like Orlando, Phoenix, or Sacramento then maybe they might make some sense and I believe they will all have room for a max contract (or could easily make the room without losing core pieces).