Here I was reading a somewhat outdated Bill Simmons chat and what did I see but this:
I think that Hollinger is making the assumption (which you have to in an "objective" system) that the quality of play is constant. Otherwise, it devolves into argument about the level of play, which can't be proved, and you wind up with (as I saw on a blog this weekend, referring to the statements you made in a column) someone saying that the Celtics and Lakers of the eighties can't be among the greatest ever because Bird and Magic weren't "athletic" by today's standards -- like they were considered athletic then.
That was my blog. And to be clear, all I was doing was observing that the overall level of athleticism on display in elite 1980s NBA matchups was extremely low by today's standards. The question of how 1986-vintage Larry Bird would fare in the NBA of 2007 is, as Mitt Romney would say, a "null set." If '86 Bird played in today's league, he would train like today's players. All things considered, it does seem to me that it's best to try to avoid making literal comparisons of players (or teams) across eras because it makes things imponderable and irrelevant.
Thus, there's nothing wrong with saying that the '86 Celtics are one of the greatest teams ever -- they dominated the league that year. There's just no real sense in arguing over whether or not the 2007 Spurs could have beaten the '86 Celtics. What we know is that the '86 Celtics performed better in terms of W-L record, point differential, etc. and that the game changed substantially over the 21 years that separate them.