I mean, personally I think "Old School" (Golden Age?) ends around Palau or Guatemala. (1-11) Over the two seasons we saw three concepts play tested and later incorporated - Exile Island, hidden Immunity Idols and one returning player per tribe. So of the players in the current season, Ethan, Sandra, Rob, Amber and Danni (5) would be "old school".
"Middle School" (Silver Age?) is tougher to pin down. I'd probably go Panama to Samoa. (12-19) It's a bit arbitrary, but here you had a lot of winners who put a premium on strategy and social game over physical prowess. And then in Samoa, Russell broke the game. In WaW, you've got Yul and Parvati, oddly enough from the same season, and Tyson (3).
"Middle School 2" (Bronze Age?) starts with Heroes vs Villains and ends with one of the Blood Vs Water seasons. I'll say San Juan del Sur (20-29). You had 6 seasons with at least 2 returning players, more than a few retired pro athletes, Jimmy Johnson and 2 transplants from The Amazing Race. From here you got Sophie, Kim, Denise, Tony, Sarah, Jeremy and Natalie (7).
And finally, there's "New School" (Modern Age?), going from World's Apart to IotI (30-39). Lots of hidden idols and a premium on BIG MOVE BIG MOVE BIG MOVE. Concepts that didn't appear to work or seemed to be born out of shenanigans. Lots of male winners (8-2). From here you have Michele, Adam, Ben, Wendell and Nick (5).
I dunno, does that seem to line up?