You didn’t spend much time in the library at school, did you? The amount of stuff not online is vast.
30 years ago only the wealthiest people in the wealthiest countries could have access to a lot of information. Now all you need is to know English and having a reliable internet connection.
The world is changing.
It's true a lot more research is online but lots of older books can be hard to find good quality pirated copies of, or have never been scanned.