Screen readers have a lot of commands for reading different sized chunks of content. In general there's probably around 50 keystrokes I use on a daily basis. It's not as straightforward as reading from top to bottom, though it can be. I can usually do a Wikipedia article without pausing at 450 or so.

If anyone is curious, here is the NVDA keystroke reference: https://www.nvaccess.org/files/nvdaTracAttachments/455/keyco...

As an interesting sidenote, screen readers have to co-opt capslock as a modifier key, then there's fun with finding keyboards that are happy to let you hold capslock+ctrl+shift+whatever.