You may be surprised at the barriers to that for a young person with parents unable to devote time to assisting them with that. Minors need a parent to sign for them(since someone has to be liable for the late fees and repair fees if a book is trashed). In rural communities there may not be a library, or transportation. The school library's book selection is almost always heavily censored, and/or hopelessly out of date.

What about the barriers involving possession of a computer, access to fairly high-speed internet, and the technical knowledge to use Torrents and video codecs and so on?

I'd say that a random person is more likely to have access to a computer and usable internet than access to the library. The "technical knowledge" involved in downloading videos involves having a torrent client and a codec pack installed (two download-and-run installers.. my gran could do it).

Then, you go to your torrent site, click on what you want, and wait. Nowadays, it's no harder than downloading any other random file from any other random site.