Just a thought.
If DA was committed to re-signing Rondo, wouldn't this team look a little bit more polished than it currently is?
DA doesn't seem confident that Rondo can lead this team to a ring as the guy. He went after Love this summer, but based on all the confirmed reports of what he offered, he didn't seem too keen on surrendering the necessary assets. And unless I'm missing something, he didn't seem too interested in other proven commodities (Afflalo, Hibbert, etc.) either.
I don't doubt that DA would love to keep Rondo on a team-friendly ($15m sounds reasonable) deal this summer, but my guess is that if he truly thought Rondo was max-worth and imperative to the future success of this club, he would have made a harder push to surround him with 5-8 seed playoff talent this summer.