granted this may have to do with the number of teams in the playoffs every year, but there i think are only 3 teams who haven't made the playoffs in the last 5 years (Minny, Washington, Sacro from my count, although i didn't look that up to confirm).
after a decade of overspending in NY with nothing to show for it (until the last 2 years) and decades of horrible play from the Clips (until luck handed them a number 1 pick), i think its clear that ownership/GM have the biggest hand in how competitive a team is. granted, those big market teams always grab the headline star. but that has always been the case. back to Wilt, Kareem, Shaq, etc. there is nothing different about LeBron or Howard going to "destination" cities. the only reason why Jordan, Bird and Magic didn't do it was because they were already there. and really, this extends far beyond sports. hell, i personally headed straight for a huge market after school (chicago). its just what people do. the big cities are attractive for tons of reasons. but these guys like LeBron, Shaq, Wilt, Kareem: they are once in a generation players anyway.
people will point to '10 and say "what about Amare? Bosh? etc". the reason that happened in '10 was because the teams with the most capspace were the teams trying to pry away LeBron and Wade. so when they didn't get them, they went after Amare, Boozer, etc.
i think what people forget about Pau and D-Will is that these guys didn't force their way to big markets. they wanted out of bad situations and the teams that went after them hardest were big market teams. NJ made the best offer for D-Will, end of story. the Pau trade was obviously fishy, but that had little to do with market-size and much more to do with GM friendliness/loyalty. same with KG. and they had to fucking pry KG away with a crowbar to get him to leave for Boston.
the interesting thing about that list is Cleveland being side-by-side with Miami. but when we have this argument, everyone just says "yeah, well Miami has the night life and the weather and the state tax benefit and etc etc". and my only answer is "well yeah. that's the point, isn't it?"
Miami is also substantially wealthier than Cleveland (although with a less engaged sports base). The thing people are missing though that's of crucial importance is how big it is to have one to two stars in basketball and how few of those exist. And because of the max salary system it makes it very easy for players to cluster in these teams. For example lets say the Nets had approached Lebron but instead of offering him his max salary (of which he took I think a 2 to 3 million haircut off what he could make) they offered him 30 million dollars per year. Now Lebron would be worth spending roughly that amount of your cap and there is no way in hell he takes a around 10 million dollar paycut (or so) to go to Miami.