Correct, these are average salaries of all 16 teams in the league. So basically I summed all salaries from every player in rosters and divided the total by 16.
I was thinking about the tanking teams, but I thought that 1) most of leagues are anyway having usually 1-2 teams that are more or less tanking and 2) that is also part of the competitiveness as if 1-2 teams are tanking, it's automatic win for other teams which is lowering the overall talent in the league
I was also trying to use BuzzerManager but I was able to get data from my own league, not any other leagues so it helps a bit but would require inputs from other BB Communities.