First of all as a fan, I don't place value in getting a player whose "as good as their contract", that player isn't winning me a championship nine times out of ten. I don't mind having overpaid players as long as they are productive.
Second of all, I don't see us getting a young PG as good as 2016 Rose unless they aren't currently in the league, and in that case Rose will be a FA before they are available.
Third, who's paying Rose 21+ million dollars? Name me a team that's paying Rose 21+ million dollars.
I'll name you one. The Chicago Bulls.
But what if freeing up caproom allows you to acquire a better PG in the summer of 2017, and that young player you trade for is equal to Rose in a year or two
I'll name another willing to pay him; The Brooklyn Nets