Making sense of generational arguments about skill development

I don't understand the following argument:

"Players from previous generations had more skill."

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"Players from previous generations were three-sport athletes."

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"Players from previous generations played more pickup games."

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"Players need to specialize earlier and train privately with individual coaches to improve their skills."

How does one acknowledge later specialization and more play in the more skilled players (debatable whether or not previous generations were more skilled) and conclude that doing the opposite is the way to develop better skills?

By Brian McCormick, PhDDirector of Coaching, Playmakers Basketball Development LeagueAuthor, The 21st Century Basketball Practice and Fake Fundamentals