Er why, exactly? Most competent adults in history have not known how to change their mind? The worlds has improved because of those who do. It seems to me that the key variable in teaching rationality is whether the student is willing. Most people just don't care that much about the truth of their far-beliefs. But occasional people do and those are the people you can teach. Thats why everyone here is a truth fetishist.
What we need is more pro-truth propaganda so that in the next generation the pool of potential rationalists is larger.
The emphasis here is on worthwhile: the idea that changing your mind, and knowing how to, has a tangible benefit, and one that is (generally, on average) worth the effort it takes to learn. If there's no particular benefit to changing your mind, then either (a) you have already selected the best outcome or (b) your choices are irrelevant.
If this is the best possible world, then I feel okay calling us doomed; it's a pretty lousy world.
As to irrelevancy, well, to think that I'd live the same life regardless of whether "Will you marry me?" is met wi...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
If continuing the discussion becomes impractical, that means you win at open threads; a celebratory top-level post on the topic is traditional.