Everyone keeps bringing up that Lebron, Melo, and Wade were on that team without mentioning that they were still basically rookies at that point. They had each only been in the league for a year, were under or barely 20 years of age, and spent most of the time on the bench as the coaching staff decided to go with more known commodities. Lets not try to act like they had prime Lebron and DWade out there.
Unfortunately, the commodities the coaches chose to use instead were chuckers like Marbury and AI, overrated players like Marion and Okafor, and ing Jefferson. Couple that with the fact that Duncan could hardly move in the paint without picking up a foul, and it's no surprise that team couldn't get it done.