Comparing 1988 to 2018 on baseball-reference.com, I don't see much difference. Gary Sheffield came up at 19, Juan Soto came up at 19. Roberto Alomar along with 2 others was 20, Ronald Acuna along with 3 others was 20. For pitching, the Royals and Dodgers brought up a 20-year old each in 1988, the Braves (and no one else) had 3 20-year olds last season. And so on. If you rank hitters/pitchers by season-age, the top 30 look pretty similar to me in these two seasons. League-wide, average age (weighted by appearances) for batters went from 28.3 to 28.1 in that span. For pitchers, 28.5 to 28.4. You get that much variation just randomly year to year. If there truly was a difference in philosophy, with a greater weighting of young'uns, it ought to show up. If you mean something further back than 1988 when distinguishing "today's" game, well, 30 years is a long time, to me. Maybe a deeper analysis would turf up something, but these simple rankings and arithmetic-means don't. Batters 1988: https://www.baseball-reference.com/leagues/MLB/1988-standard-batting.shtml 2018: https://www.baseball-reference.com/leagues/MLB/2018-standard-batting.shtml Pitchers 1988: https://www.baseball-reference.com/leagues/MLB/1988-standard-pitching.shtml 2018: https://www.baseball-reference.com/leagues/MLB/2018-standard-pitching.shtml