1. Well, Ainge might do again something spectacular in the 2007-08 fashion, but I think it is highly unlikely. We all followed the Love Affair this summer. We were not even close to getting him. (And even with Love we would not be a contender).
And, besides, we don't want again a team with a short expiry date like the 2008 one. I might be wrong, but I think the plan is to form a core of good players in their mid-twenties who will have been playing for some time together under the guidance of Stevens. This will take time, but once in place it will make us a top-5 team for a good period of time. It is the Philly plan executed in a better way.
And, yes, building a contender takes time and/or luck. The Cavs were really lucky with LBJ and OKC with KD, but what about the other teams? Have you seen how long it took the LAC to build a contender? And look at all the other teams struggling (so far with only partial success) to get there- Washington, Portland, Chicago... What makes you think we can make it faster than they, especially given they right now have way more assets than we do?
2. The problem with seriously competing for the playoffs is that we will most likely end up 9th or 10th, which is the worst place to be. I think we will push for the playoffs only if (around December) we feel confident we can get something more than the 8th place, but this is highly unlikely.