Yes, self-reliance is a great ideal. But.
Lots of smart folks like to quote Papa Heinlein's immortal words from "Time Enough For Love" concerning Lazarus Long's feelings about specialization and humans, as does Glenn Reynolds in his October Popular Mechanics column on the end of self-reliance in American society. I've uttered the phrase "specialization is for insects" on more than one occasion.

But it's time that someone made a deeper point about this paragraph (which IIRC was a chapter heading quote and not part of the story.) I can't recall if Mr. Heinlein gives us a clue to the context of the quote. Perhaps it's one of the chapters where Lazarus Long is undergoing geriatric rehab yet again, which could mean it was intended as an example of the sort of wisdom that is being passed on to the descendants who are listening to Long's recollections. Or perhaps it heads up a chapter describing Long's time spent homesteading with Dora (his great love and normal-lifespan spouse.)

IIRC, in the former case Long would have been about 2,400 years old, and in the latter about 900. In either case, it's the remark of a man WHO HAS LIVED MANY MULTIPLES OF A NORMAL LIFETIME.

Hey, I'd be a world-class neurosurgeon and an expert at tiddleywinks, too. Meanwhile, I'm going to do some prioritizing in what's left of my fourscore-plus or so years. If that means finding time for computer games instead of learning to butcher a hog or pitch manure (to say nothing of reading journal articles while waiting for AAA to change my tire, though I'm not yet that far gone...)

Well, the species will survive, I think.