Love was really the ideal guy to have traded for, assuming his Boston trip meant he was open to playing and re-signing here. He was still young (25) and they would have had a year to see him and Rondo together. There isn't really another young star that is going to be available for awhile as they are all in good situations or are going to be locked up as restricted free agents.
Even if the Celtics get lucky with the lottery next year and end up with a top pick, I don't see who would be available that would be worth dealing for. Anthony Davis, Aldridge, and Cousins aren't going anywhere, and Marc Gasol is old. Hibbert, Sanders, Monroe, DeAndre Jordan, Asik et al. are interesting names and might be useful players, but they're not someone you overpay for to come to a team that has talent holes elsewhere.
This is why I see Ainge looking at the landscape and deciding to go full rebuild (which they're basically doing already only Rondo is still on the team). As the available trade options dwindle, their draft picks become more valuable to keep than to deal, just as Smart becomes more logical as the future PG than Rondo considering the roster's average age.
Every draft is obviously critical, but they really need a center or a wing scorer in next year's draft. Not having those roles secure for another year would be another year's delay in the rebuild. Without a reliable wing scorer or a defensive big man you can't really even consider the team legitimate.
1.) You don't know for sure that Aldridge, Cousins and whoever else aren't going anywhere.
I am willing to bet a year ago, no one thought Kevin Love was going anywhere.
You may be right, but you also may be wrong. It seems every year, there's always at least one NBA star who's rumored to be on the trade block. Only guy you mentioned that I could see staying where he is, is Anthony Davis. He's still on his rookie contract so I doubt New Orleans even lets him flinch until he hits unrestricted free agency.
Call it a hunch but as for Cousins, I've got a feeling that if Sacramento doesn't make the playoffs next season, there's a VERY good chance he becomes the next disgruntled NBA star looking to be moved. Granted, doesn't mean Sacramento moves him, BUT if we've got a top 3 pick and other "assets", you never know.
And with Aldridge, he will be a free agent next summer (unless Portland locks him up before hand.) If he's still set to hit free agency next June, DA could either come calling Porland with assets to deliver in a sign and trade or he could just go after Aldridge outright. After all we will have over 30 mil in cap space next summer.
2.)I sorta disagree with your assessment of guys like Monroe, Sanders, Jordan, Hibbert, etc.
If Rondo is still here, then a guy like Deandre Jordan paired up with Rondo looks awfully good and is a really good start to geting back on track. All that would then be missing is a very effective scoring option to go along with Rondo and star B (insert name, Jordan, Hibbert, Monroe, whoever.)