Fitness I think.
The top tier of fitness across a number of activities has never been more competitive.
I get the impression that in previous centuries (and maybe even previous decades) individuals who were particularly coordinated and fit could succeed in many different professional sports.
Now, each and every physical activity… no matter how niche seems to have an incredibly competitive upper echelon, wether it is soccer, cricket, marathon racing, ping pong, archery, rock climbing, surfing, or whatever. You need to dedicate extraordinary amounts of time and energy to that activity to be the best.
I suspect this hasn’t always been the case. I wouldn’t be surprised if there are more professional athletes now relative to the population size than ever before.