The luck involved of first signing Aldridge and then getting Kevin Love (or someone similar) via a trade is on the same odds of luck involved in getting a top 5 pick.
Like I mentioned in an earlier post, we have enough assets comparable to what Orlando got for Dwight. In other words, we have enough assets to trade for just about anyone who becomes available on the block. Furthermore, as LooseCannon posted in another thread, we will have enough cap space for a max free agent, too. So, the only odds would be Ainge actually converting the assets/cap into two stars. Given Ainge's history, I'd say that's pretty darn high, especially when players will have the chance to play next to Rondo. Furthermore, as it stands, this team is going to get a 5-10 pick anyway. I've probably seen 10 different names go as possible top 5 picks. That speaks volumes about how top-loaded this 2014 draft is. What are the chances one of those high potential players falls into the 5-10 range for Ainge to draft? Again, pretty darn high.
Meanwhile, what are the chances we get even value in return for Rondo? What are the chances that other teams start tanking and blow up their team even worse than Boston? Even if that doesn't happen, what are the chances we get a top 3 pick anyway? Even if you finish as a bottom 3 team, you aren't guaranteed a top 3 pick. Furthermore, even if we do get a top 3 pick, what are the chances a FA would rather come to Boston when a rookie is their best player, not Rondo? What are the chances we build up a contender around a Wiggins-type rookie if one of the greatest players of all time needed to switch teams before winning? And the list keeps going...
I don't know about you, but I'll stick with not tanking rather than tanking. You're right in that the probability of anything working is slim to none, but I'd rather maximize my opportunities (and consequently maximize the probability of succeeding), rather than sticking to one and only one option.