I'm having difficulty understanding

First, let's say you're a developer for CoolDistro. At some point you meet ExperiencedDev, who after a round of introductions signs your key. You sign theirs. You get the keyring for CoolDistro, and since ExperiencedDev signed pretty much everyone's key, you're pretty much set. No keyservers in sight.

But let's say you're a random guy, you went to FOSDEM and signed more than a hundred keys. You're well connected now. And you want to verify the key on the Tor browser. What do you do?

1. You get the signature, you try to verify it, and gpg tells you: "nope, this isn't trusted!". You don't have the signing key. Damn.
2. Okay, there's gpg --recv-keys, right? Nope, there's no default keyserver.
3. You google for, and configure gpg to use a damn keyserver. You get the key. Still no dice. The key isn't trusted, because you didn't sign that one.
4. You figure that somebody you met, at some point, must have signed it. Time to make sure you have every key you signed, and that you refreshed them from the keyserver. Now it should work. But it still doesn't.
6a. GPG's trust model works well for Alice -> Bob -> Carol chains. But it can actually extend further. What if you want to check an Alice -> Bob -> Carol -> Dave chain? Well, you're stuck. You might know who you signed, but if you don't know Carol, how do you find out you need her key? Here you can take on the desperate resort of recursively downloading the key of everyone you signed, plus every key *they* signed, hoping it might help. Happy scripting! And dealing with a key database of several thousand people, the vast majority of which you've never met.
6b. You might actually know about https://pgp.cs.uu.nl/, which some random guy runs and which might vanish at any moment, and which doesn't cover every key in existence. But it helps a lot.
7. What? It still doesn't work!?. GPG isn't happy with just signatures, you need to tell it how much you trust that key. Do gpg --update-trustdb and fill in the missing info. Things get fuzzy here. How much do you trust guy #53 of 120 you met at FOSDEM? Do you remember how well you checked his ID? Uhh... You get that done, and finally, that WORKS.
8. Time to celebrate with a drink of your choice.

Why, nice and easy, isn't it? It'll only take meeting a lot of people face to face, laboriously signing a hundred keys, then spending a day or two figuring out the above, and you can finally make some use of this web of trust. If you're technically minded enough to understand all that stuff, and have the patience for it.

I'd be willing to bet that the number of people who've done the above isn't very large. I've done it, and it actually worked, but boy is it annoying. You need to be a pretty special kind of person to put up with that.

PS: While writing this comment I tried to get the Tor Browser's current key to make sure I wasn't missing anything. It's got "100304 new signatures" on it. Wheee.