How on earth can it be "easier" to create a dynasty in the NBA, which has a salary cap, as opposed to MLB, which does not, and which has seen the mega-payroll teams like the Red Sox and Yankees continually in contention, and usually in the playoffs?
I'm not sure, but the facts seem to show that it is far easier to do it in the NBA. I suspect it's because you only put 5 players on the court at a time and one player can make you into a great team very quickly. That doesn't happen in the NFL, MLB or the NHL. So although they have all of those constraints, you only need to hit on one player i.e. Shaq, Kobe, Tim Duncan, Chis Paul (hopefully) or Jordan and you are a Championship team. One great player does nothing for you in MLB. Barry Bonds was probably the best hitter in the game ever for a 5 to 10 year period and his teams never won a Championship. Can you imagine the best player in the NBA for a 5 to 10 year period not winning a championship during that time? I can't because that one player means so much in the NBA when compared to MLB or the NFL and NHL for that matter.
Whatever the reason, you see dynasties more often in the NBA. In MLB, even the money the Yankees spend doesn't get them the ring. When they were on a hot run in the 90's it was because they spent years building a great farm system, not because of the money spent on free agents. And the Sox have been spending money for years and were only succesful when Theo Epstein came in, built the farm system and made some brilliant trades. Look no further than the Cubs and Redskins to see that you can't buy a championship in the NFL or MLB.