No chance they are all 70+ years old! Do you mean if there was a time machine that brought these past player in their athletic prime to todays game? Well conditioning and coaching beginning in childhood has advanced so much I don't think they would have the overall defensive or athletic game close to todays players. Baseball and Football have been around since the 1800's so those sports already had long established talents playing the game well before the 1950's and 60's. In those decades the top baseball athletes weren't terribly different from todays baseball players. But in basketball now there are millions of kids competing for NBA spots so to be one of the 200 best players on the planet you have to be a hell of a physical talent with skills. Back in the 60's there was no where near the same competition. But I'd imagine a few of the elite guys of the early NBA would have a place in any era if they had the benefits of modern training. The silly thing is back then when Russell and Cousy won their first title they only had to beat out 7 other teams. The league didn't have rules to even out talent. There was no minimum payroll or salary caps or restricted free agents. Its much more of an accomplishment to be one of the two teams in the conference finals of todays NBA than to be one of those past champions.
Yep and some of the teams barely stayed in business, so they would often sell one of their best players to.....Boston in order to keep their doors open, or in this case they obtained players when they did go bankrupt. "One of the first great players to join the Celtics was Bob Cousy, whom Auerbach initially refused to draft out of nearby Holy Cross because he was "too flashy".[8] Cousy eventually became the property of the Chicago Stags.,[9] but when that franchise went bankrupt, Cousy went to the Celtics in a dispersal draft"