It is no more a question of whether he is worth the max or not, but if we have other options.
Rondo is the face of the franchise right now. Every single of the new guys (rookies or not), when asked about what excites them the most about this season, pointed to Rondo. Not the banners, the traditions, the coach or other players - only Rondo. Believe it or not, after 1 year away, Rondo is still recognizable, rumor worthy star, players are excited to play with.
We ain't getting anybody that exciting (for players or fans) in a trade. Solid peaces, potential, picks - yes, but not a face of a franchise. As others have pointed out, somebody is bound to offer max sheet to Rondo next summer. We either match or lose him.
So, Options are:
- trade him and have a looong rebuild ahead, but with a slightly worse starting point than Bucks, Sixers, Suns etc...
- keep him on the max price (a discount for a Non-trade clause?) and try to build a contender in the next years.
Good thing - with all those picks, we have either option available.