alt Hacker NewsI have to assume the author listed these times based on how long it would take for someone to follow along with the blogs that they linked to, which demonstrate stripped down simple versions of these things. Like the POSIX shell example just implements a few basic things, but leaves out a lot (and says so).
This is the point, yes! Toy software is not production-worthy. It might not even be sufficient for your own personal use. It's about building proof of concepts and rapidly scouting out the terrain of a field you don't know much about, and getting a souvenir to remember the experience with.
Oftentimes I find that I enjoy one of the projects so much that I take it further than 'toy', but that usually ups the time estimate by an order of magnitude.