Anyway, as to what’s changed in the last fifty years, the main thing is that MLB makes way way way way more money. And that affects the single biggest change in MLB:
FREE AGENCY. As it happens, 50 years ago was the first year of free agency.
In 1975, the average attendance for an MLB game was 15,403 per game, which was the fourth highest average in MLB history and the three slightly higher ones were all 1972-1974. It would never be that low again or even close - it jumped 10 percent in 1976 and shot up from there. This year so far the average is 27,500 and it will be higher at season’s end. The doubling of per game attendance (which is across 30 teams, not 24 as existed in 1975) is despite the fact that inflation adjusted ticket prices are higher (though not by a ludicrous amount.)
Furthermore, teams today make WAY more money from advertising, marketing deals, merchandising (one of the most obvious visual differences between a 1975 MLB crowd and a 2025 crowd is how many people are wearing MLB caps, jerseys, etc.) cable deals, and the like. MLB teams do a good job trying to hide their actual revenue, but they’re making boatloads of it, and that’s why the players get paid more than ever. Their becoming free agents is the main reason, but note free agents are getting more than they did ten years ago, 20 years ago, and so on.
Everything about MLB revenue and spending is up. It’s not just that the players are making more; everything is. The quality of stadiums today that the teams play is is absurdly, ludicrously superior to what exists now; no stadium in 1975 matched the quality, comfort, cleanliness, or overall professionalism of places like PNC Park or whatever San Diego calls their ballpark now. Even the stadiums that have lasted since then like Wrigley or Dodger Stadium have been substantially improved. Multi-use stadiums have been almost entirely phased out in favor of baseball-specific facilities. Why? They can afford to. Actually, now that Toronto has converted their stadium to baseball-specific and the A’s have left Oakland, I don’t think anyone plays in a multipurpose stadium anymore.
Teams put FAR more emphasis on training, medicine, and the science of sport. They put more emphasis on international scouting (helping with another big change - more players from different countries. Japanese and Korean players were not in MLB in 1975.). And yes, they more more emphasis on analysis. This is all a natural outgrowth of the fact that there is way more at stake.