The article mentions that without free play, kids can not develop their own interests, which (my thinking) might leave them vulnerable to taking on unpleasant and unfulfilling jobs. The ability to be docile and execute orders does not really put you in control of your life, quite the opposite really. Yes, you need some continuity to build something complicated, but who knows, if you are really interested, you might be motivated enough without discipline.

Also, you assume that free playtime by children will automatically be spent on useless activities. While I am not convinced that there is nothing to learn from video games, I think kids will choose projects by themselves, and they will learn how to execute on their ideas.