How might such a world (of universal programming literacy) come about?
Most likely from a continuing trend to automate the way a lot of work gets done, and then people would learn programming as a way of engaging with that world.
For example, instead of spending half an hour in the supermarket or even 10 minutes browsing a supermarket site on the web, you might be able to compose an augmented shopping list on your phone.
4 bread rolls
Could become :
prefer("Pink Lady" or "Fuji").
Similar little languages can be developed for most activities. So I’d guess that we’ll all be writing little scripts for robots or large automated services. There’s an assumption that people must prefer navigating rather laborious graphical interfaces to get stuff done. But if they were more programming literate they may learn to use and love such small scripts instead.