That this story can thrive on HN every few months is a strong indicator that a nontrivial chunk of the userbase is 16.
Having never seen this before is perfectly reasonable if you're new.
My point is that age is irrelevant. "Newness" may be, but that doesn't imply age.
In the proud tradition of founders generally solving problems that mostly affect themselves rather than the rest of the population, I propose the startup idea of a hackers bookshelf startup. Not the first time its been tried, its a hard problem which means its a good startup topic.
[1] https://www.hnsearch.com/search#request/submissions&q=cargo+...