It's a different game and players are trained differently. The old player's when I started watching the game had done national service, they trained on assault courses. They had incredible stamina, they could play three games a week, on heavy pitches with full on tackling. No substitutions back then and later just one per game.
Today's player's are ripped. They are thoroughbreds and are probably faster than the old player's. But I doubt they could play three games a week on heavy pitches against psycho defenders.
I don't think today's player's are better than the old ones skill wise. George Best and Pele were the best I saw. But not many games were filmed back then and only from a camera at a fixed angle.
To be honest there's nothing about the game today that I like compared to the old days.