Trying to reply to all of that at once, with documentation, was more than I could manage before bedtime, but let's try starting off with a few points which should be easiest to resolve. Here's a good starter.
of COURSE the all time numbers are going to be skewed toward big market teams -- the early league was composed mostly of those teams
Earlier, I didn't examine the NBA before 1955, because I considered it to be SO different from now that there was no point in even looking at it. The league started out with a $55,000 salary cap, so if you had a 2,000 seat arena, and charged $1 a ticket, you had a viable business. And who were the champions in the first years?
1. Philadelphia
2. Baltimore
3. Minneapolis
4. Minneapolis
5. Rochester
6. Minneapolis
7. Minneapolis
8. Minneapolis
9. Syracuse
Philly is a major market, but I would say the others are all minor. Can we chalk up that much as undisputed?
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EDIT: For those who like old NBA trivia, here are a list of the teams that vanished without a trace by 1955: Anderson (Indiana) Packers, Baltimore Bullets, Chicago Stags, Cleveland Rebels, Denver Nuggets, Detroit Falcons, Indianapolis Jets, Indianapolis Olympians, Pittsburgh Ironmen, Providence Steamrollers, Sheboygan Redskins, St. Louis Bombers, Toronto Huskies, Washington Capitols, Waterloo (Iowa) Hawks. The Nuggets went belly up in 1950, the current Nuggets team is descended from the ABA's Denver Larks (founded 1967), later renamed the Denver Rockets. They had to change their name to join the NBA, since Houston already had the name "Rockets," and revived the name of the long-defunct franchise. The Baltimore Bullets similarly did not become the Washington Bullets, they went bankrupt in 1955, and the name was taken by another franchise (the relocated Chicago Zephyrs) 8 years later.
As you can see, life could be tough for smaller franchises even then. Some major cities, like Chicago, had big problems maintaining a solvent team, but most of the attrition was elsewhere.
Also, during the mid-late 1950s, the trend of moving franchises to larger markets began. The Tri-Cities (Moline, IL; Rock Island, IL; Davenport, IA) Blackhawks became the Milwaukee Hawks, and then the St. Louis Hawks. The Fort Wayne (IN) Pistons were relocated to Detroit, and the Rochester Royals went to Cincinnati. Minneapolis lost their Lakers to LA.