Sure we do. In the Boy Scouts for example, though I just learned it from a book. I suspect a large percentage of people on HN would know how to start a fire from scratch.
It's almost impossible for me to believe that even 1% of HN readers can start a friction fire.
And then you'd have people who learned in some outdoor survival course, etc. Obviously this will vary from country to country, but surely it's higher than 1%?