There's also a complexity explosion to factor in, and saying that there was a time before Google and Stack Overflow seems a bit dismissive of that. Chances are, your app today is built on at least a dozen dependencies that require documentation and reference lookup several times throughout any given day.
Point taken, but reference material can cover a lot more than API docs. Changes in dependencies, dependencies of dependencies, and their change in source over time are often critical pieces of information. Further, it's difficult to cover all possible material for dependencies that have been taken for granted; OS, HTTP server, drivers, and unexpected complications like OEM-level defects in specific revisions of hardware models are difficult to account for.