The "old" Internet is still there in parallel with the "new" Internet. It's just been swamped by the large volume of "new" stuff. In the 90s the Internet was small and before crawler based search engines you had to find things manually and maintain your own list of URLs to get back to things.

Ignore the search engines, ignore all the large companies and you're left with the "Old Internet". It's inconvenient and it's hard work to find things, but that's how it was (and is).

What safeguards would be in place to prevent this parallel internet from also, with time, becoming a dead internet?

A̶O̶L̶ Humans Online

Internot.

What would stop them from scraping it and infecting it?