It’s been alluded to already, but the longevity of players is massively improved by the pitches and rules compared to 30 years ago.
Diet has also made a difference, however, it should be noted that a lot of footballers in days gone by, lived exceptionally healthy lifestyles. It’s not new for people to eat well and exercise correctly at individual level, it was just introduced to club culture in the 90s. Stanley Matthews for example was very well known to live an extremely healthy diet and he wasn’t the only one.
One aspect I have not seen mentioned too much on the thread so far is medical improvements. I can’t really tell you enough how far this has advanced, particularly for modern sport. The money generated makes this a multi billion dollar industry nowadays, where as 50 years ago if you got a serious injury, that was possibly it.
To highlight two massive football characters who had serious injuries in yesteryear, an serious knee injury did for Brian Clough in his prime. Ligament damage in a serious knee injury did for him, he’d be back in 9-12 months now for sure. Dave Mackay had a serious leg break, he’d almost certainly be back in 9 months or less nowadays, yet it took 18 months and nobody would trust him again. Famously, Peter Taylor was watching Mackay and thought he was the same player as before the injury and was amazed Tottenham couldn’t see it. He told Clough and he replied that Mackay was a past it crock (because that was the norm for someone who’d had a serious leg break). Taylor convinced Clough to take a punt and Mackay went on to have legendary status at another club.
Medical improvements would have massive differences on numerous players from years gone by, from minor knocks to recover and recuperation, to saving careers entirely.
Players have a union and their is a reason players don’t protest, it’s coz they actually don’t mind playing football.
It’s an excuse for managers.