It's amazing to me how by picking just a few players/coaches/teams one can "cover" an impressive stretch of years of NBA Finals participation. You can cover 1991 to 2009 with just four coaches: Phil Jackson, Gregg Popovich, Rudy Tomjanovich, and either Pat Riley or Avery Johnson. Every single finals over a 19-Finals span has featured one of those four guys. From 1991 to 2007, every Finals but one featured either Michael Jordan, Shaquille O'Neal, or Tim Duncan. Oddly enough, not one single Finals featured two of them. From 1980 to 2009, 26 of 30 NBA Finals have been won by either the Lakers, Celtics, Bulls, Spurs, or Pistons. 9 of the past 30 Finals (almost 1/3rd) featured two of those five teams.
Because NBA plays only 5 at a time, and your starters tend to play 75% of the minutes or more. A collection of good role players can fit with two superstars or one superstar and two stars to make a dynastic team. You generally can't say that about other team sports.
It's actually quite simple. The NBA wants teams from large markets to be the elite teams of the league. That's precisely the reason that they have a "soft salary cap," as they refer to it: so that the big teams can be able to get away with crossing the salary threshold in ways the smaller market teams cannot (in 2007, the Knicks crossed the threshold by 69%. Imagine if a team like the Spurs could get away with that).
The NBA is a superstar dominated league. From 1991 until 2003 the team that won the NBA championship was the team with the best player. Look at baseball, Barry Bonds is quite possibly the greatest player of all time and is the best baseball player of the last 25 years, yet he's only been in one world series. In baskebtall someone of his talent would have won 4-7 championships.
From 1984-2005, every champion came from a group of 6 teams - Lakers, Celtics, Pistons, Spurs, Bulls, Rockets - and all 6 of those teams had multiple championships. Since 1980, those six teams have 28 of the 30 NBA championships. Personally....I like it. Its like college sports. There is a hierarchy. I have always found the parity in the NFL and MLB a bit boring. Championships carry less meaning because it seems everyone wins one. I think sports is more fun when you have big boys and Cinderellas.
You know, if you look at the entire history of the NBA, it's dynasty after dynasty, with the 70's as the only decade in which there weren't one or two dominant teams. 50's--Lakers 60's--Celtics 70's--Knicks had a couple of early championships, Bullets went to three or four finals from 74-79, but there were 8 different champions OP and others have already discussed the 80's on.
The fewer players on a team, the easier it becomes to dominate a sport long term. Consider the Red Wings or the dominance of Nadal, Federer and Tiger Woods.
1. the impact a single player can have, thus enabling a team with jordan/hakeem/shaq/duncan to compete year after year depending on management's ability to add role players. 2. consistency of performance. this is its main advantage over baseball. somebody hitting .320 with 40 HR's and being almost the best player in a league one year and then hitting .280 with 25 HR's and being just a nice player the next year isn't really that weird in baseball. however, it would be really weird next year if lebron james, kobe bryant, dwyane wade, and chris paul weren't among the top 5 players again. and then there's intra-game consistency. again, while a player might shoot 40% one game and 55% the next, someone like kobe/lebron is going to be the best player on the court almost every night and can potentially will his team to a win at any given time. since hitting curve balls and 95 mph fastballs is fairly hard, even a great player can go 0/4 and have essentially no impact on a big baseball game. or a scrub can hit a 3-run homer and account for 75% of his teams runs in a 4-3 win. you're probably not losing a title because kobe bryant suddenly can't dribble and marcin gortat is putting up a 40/20 game. 3. a soft cap. although not at all for the reason Hpslugga is apparently intent on derailing (and making his typical bcs-inspired "outlandishly vain" value comments) this thread for. the soft cap allows teams to resign their own players and keep teams together so they can go as long as the players are in their primes. this is the biggest advantage over the current enforced-parity world of the NFL. the teams who have most "abused" the soft cap - paul allen's plazers, cuban's mavs, dolan's knicks - have nothing to show for their efforts. while SA and LA, two teams that don't go over the luxury tax (the lakers may have this year, not sure) have a ton of titles. but mostly just because they could keep the teams together, not by buying talent. 4. playoff series. someone else already alluded to it with the fractions post, but with 7 games to decide who moves on, the better team in a matchup almost always moves on. sometimes the overall better team might lose because of matchup problems (mavs/warriors being the most obvious example), but between those 2 teams, it's very hard for the lesser team to pull an upset when they have to win 4 games. as such, the best teams almost never get knocked out on a fluke and dynasties don't end for no good reason.