Right - comparative advantage and all that. The problem then though, is that we end up with a large population of the mentally obese, growing increasingly distrustful of the intellectual elite who are supposed to do the thinking for them, because they represent a different youth tribe. We probably want to be encouraging intellectual effort for it's own sake in the way we try to encourage sports - even if you're not an athlete, you should take pride in running every day before work or whatever.
One of the big variations I see between people is the amount of energy they habitually put into thinking, and I haven't seen this discussed anywhere.
General advice about improving health and lowering intellectual friction would seem to help increase the ability to think, and ideas like "take five minutes to consider the problem" adds impetus, but I'm not sure what the general difference is between me and most people, or Yvain and me.
Intellectual drive isn't an unalloyed good-- cranks have high drive combined with low self-editinig, and some types of depression include a compulsion to think about topics that cause misery and/or inertia. Part (all?) of the value of meditation is getting some time off from thinking. Still, increasing intellectual drive would probably be a good thing for a lot of people.
Has anyone found that rationality training or anything else increases the default desire to think?