I don't think they need to teach all of CS; I would agree your average language tutorial probably doesn't need a chapter on tree traversal or transitive closure

I don't think they need to teach all of CS; I would agree your average language tutorial probably doesn't need a chapter on tree traversal or transitive closures or whatever. I do think they should all teach IO, though. If I could only pick 1 part of a language to understand really, really well it would be IO. The vast majority of apps spend the vast majority of their productive time on IO. Your average CRUD app is almost entirely IO. The user sends IO to the app, the app send IO to the database, the database does IO to get the results and then the IO propagates back up. The only part that isn't basically pure IO is transforming and marshalling the DB records into API responses. If you you add parallelism, that's like 98% of what most apps do. Parallel IO dominates most apps.