ohhh boy.... You're gonna enjoy this post my friend.
Actually Geoff The Hero was moderately famous before the famous you're talking about.
Geoff was a part of the "Gamelife" which was a "major" YouTube channel which started around the time YouTube first started getting very popular. So he pretty much became famous by the exact same way DSP did.
They were old-world famous in that companies like MTV/Viacom offered them an entire TV show, they got flown out to game lauinches and events etc.
View attachment 375221
Gamelife video featuring Geoff:
Guru Larry vid covers the rise and fall of "Gamelife" (Geoff's section starts at about 10 minutes in) BONUS: it has darksydephil mouthing off at Machinima!
(Even Guru Larry said they had autism pretty flatly)
https://encyclopediadramatica.rs/Gamelife
http://web.archive.org/web/20081204...com/boston/recroom/19081-revenge-of-the-nerds
http://gamelifeshow.com/abouthost.php
EDIT:
Oh yeah, I'm rewatching it now, and the main guy behind Gamelife (Andrew Rosenblum) had an argument with his GF and sent a death threat and got arrested which lead to the whole "gamelife" shit falling apart pretty quickly:
https://www.wired.com/2007/04/gamelife-host-a/