So this is crazy...
Amongst the top 200 WAR players, the following active players are there:
Trout #35 at just 31. He will finish in the top 15 ahead of Mantle. It's unreal the Angels can't win with him.
Miggy is next at #87. Its the end of a hall of fame career.
Joey Votto is next at 98 and he should end up near Miggy
Goldy is next at 117. He did most of that with the Dbacks. He might end up ahead of Miggy and Votto but hes 35 so the cliff is coming.
130 is the great Mookie Betts. Betts is putting in a 6 WAR season right now at 30. He will end in the 50s is my guess.
Evan Longoria is 131 at the end of his career. He won't make the hall of fame but what a career it was.
Nolan Arenado (175), Manny Machado (177, how is he already 30?), and Freddie Freeman (#181) are the final actives in the top 200 but all are over 30 already. They wont crack the top 100
We are absolutely not in a great era of baseball right now.
Baseball has been around for so long and has such accurate stats that it is almost impossible to have multiple guys projecting as top 10 or even top 25 players at the same time.
If you went back to 50 years ago and watched a pro basketball game, it would have very little in common with the modern NBA, a pro football game from the 60s would be an alien experience... but you could go back 100 years, watch the Yankees and the Giants play in the World Series and see a game strikingly similar to modern baseball, the fastballs wouldn't be as fast and the hot dogs would be a bit frightening, but the action would be the same sport we watch today.
We compare the stats of guys who played, literally, over 100 years ago to today's stars. These other sport leagues didn't even exist yet, and wouldn't take anything resembling their "modern" forms for another 50 years.
There are guys in the top 50 in WAR in baseball and their daddy probably fought in the civil war. I wouldn't be surprised that if you spread out that top 50 by decade, that it's rather balanced over time, with today being right on par in terms of "star power".
Except maybe in pitching. Modern pitchers don't get enough innings to compare.