From strictly a video game subsection breakdown - Lack of leadership direction (Lowtax) and competition.
SomethingAwful (which would really be an offshoot of the planet* network) had the major benefit of being the largest video game forum of it's time (early 2000s). Imagine what a resource it was when playing something like early World of Warcraft (which, at the time, had 0 mod support, discord wasn't invented yet, no dungeon/duty finder, no WoWhead, no easy to use voice chat - nothing). It was literally one of the only shops in town and it had tons of clout (a lot of industry insiders would post there). Because there were tons of people who wanted to have fun, it was very easy to set things up - which paved the way for dumb goon things like massive PVP shitstorms, firework shows, raids, whatever - which became SA Advertisements.
In addition, Lowtax also had tons of free content generation for his website from these same people. This was before people had a notion of making money on the internet (this is pre youtube ADS, pre-twitch, pre-Mixer, pre-streaming in general). People were making stories, photoshops, video content, etc and Lowtax was the only one making money from any of it, for years and for free.
Eventually, the video game landscape started to change and other sites started to rise up and Lowtax in his infinite wisdom decided to do nothing. It started to fracture slowly, with writers and other content creators going elsewhere for a larger audience or actual, real money. With those creators leaving, they took thier fans with them. So now Lowtax was bleeding content AND audience and really had no way to replenish them, because Lowtax wasn't involved with thier success at all - it was all other people who did it for free. Using the WoW example, it was the people who led the guilds, the raids, wrote the articles, made the videos, etc and not Lowtax, so when those people broke off and wrote for other sites, started streaming, set up a Patreon, whatever, Lowtax had no idea what to do.
It isn't just Video Games, either, it's the same story for every SomethingAwful vertical - Lowtax didn't animate (Shmorky did), he didn't write many articles (everyone else did), he didn't build the forums, he wasn't involved in Let's Play/Streaming until way later (and too late, tbh), he wasn't even the "likable management guy" (that was Fragmaster).
The wokeness is basically just a situation of "what's left" when everyone who likes having fun leaves for greener pastures to a million different other sites. Lowtax is there because it's easy, but also he never actually developed any skills despite his proximity to talented people for huge periods of time and opportunities literally being constantly handed to him.