They really can't...

They can learn some critical thinking later, but it'll never be the same as if they learned it as children.

Like if you found out you were in the Olympics for the 100m sprint next year. You could improve your performance in a year, but you'll never match someone whose trained their whole life at it.

For all intents and purposes every improvement between now and next year aren't gonna matter, last place is last place, regardless of your time.

That's what it would be like to not learn critical thinking until an adult.