That’s the fundamental dilemma of not just the web, but the Internet, as a pull medium opposed to a push medium like television or radio. A human can not remember every URL. From your blank web browser you can only go to URLs you know. Then the only web pages you will ever see are ones that are linked, directly or indirectly, from the ones you know.
Most people only know Google, Facebook, etc. Anything that isn’t linked to from those sites effectively does not exist.
But it does exist. It’s a whole forest full of trees falling and not making a sound. It’s up to you to do what you can to find it.