with my loose delineation of eras being

'46 inception thru '76 merger
'76 merger thru '98 lockout
'98 lockout thru present day

outside of the most cursory-level discussions, it really only makes sense to compare players to their peers. there are just way too many factors that vary over time.

i don't really even like comparing today's players to the 80s guys, let alone the 50s and 60s, that might as well be the high middle ages.

take something as basic as free agency. the modern version of which didn't really exist until the mid 90s. in today's league it just isn't realistically feasible to keep a core together long enough to win 11 titles like russell's Cs or make 9 of 12 finals like magic's lakers. the duncan spurs being the rare exception.

the three point line. introduced in 79-80. took players and coaches a decade to really embrace and incorporate it. bird averaged less than 2 3PFGAs per game for his career. in today's league he'd be hoisting 7 or 8 a game like durant, love, curry, harden et al. his scoring average might've been 5 points higher.

nutrition. sport science. travel conditions. rule changes. expansion.

etc etc

just stick within eras. keep your search terms narrow. casting too wide a net just turns it into apples v. oranges.