He was the first to publish an open way to communicate with him in order to out the corporate crazies, and readers did in droves, explaining the inanity of their workplace and getting secret retribution for stuff they clearly couldn't complain about publicly.
A good percentage of youtubers and substackers today actively cultivate their readership as a source of new material. They're more of a refining prism or filter for an otherwise unstated concerns than a source of wisdom.
Doing this seems to require identifying with your readers and their concerns. That could be disturbing to the author if the tide turns, or to the readers if they find out their role model was gaming them or otherwise unreal, but I imagine it is pretty heady stuff.
I hope he (and anyone facing cancer) has people with whom he can share honestly, and has access to the best health care available.
I didn't understand it much as a kid, but later read an old copy of his book on how offices and office culture works (basically each chapter is Scott describing office did functionality with a liberal sprinkling of related Dilbert comics) and literally almost everything was 1:1 with the company I was at, only it was a good bit toned down of course. The beauty was that it was somehow generally applicable anywhere a company gets above a certain amount of employees. There was a lot of good information there such as how the company tries to get you to poop on yourself in your performance review in order to justify not giving you a raise or firing you (see - you yourself said that you needed improvement in working with others). There are many other insights as well that I found useful in my career. A lot of it is common sense, but it helped me come to terms with the irrationality of the corporate world. Every few years I reread it and find it more applicable than before.
He later wrote a book on why he thought Trump beat Hillary and it also had a ton of insights I didn't think about as I'm not a marketer. Anyone on Hilary's campaign team should read it. Of course it doesn't cover how Hilary was painted as some kind of evil queen from a fairy tale since the 90s. Scott kinda acts a bit nuts in this book though as he goes off on frequent tangents about being a trained hypnotist and how he recognized that Trump was doing the same thing. One of the many examples was that both of them went on SNL, but Trump attempted to act presidential, while Hilary was attempting to act more like the common person and it just didn't work and came off unprofessional. He also flew in a plane that looked like Air Force One and gave press conferences with a little fake Oval office desk.
Adams also came up with the term "confuseopoly" to describe companies that make it so hard to compare products and companies that you have to purchase on vibes. Economics textbooks use it now along with his blog example of trying to buy a truck. I see this dark pattern everywhere now.
I hadn't really thought about the twitter angle you talk about, but did notice his blog started changing back in 2016ish. I just attributed it to him running out of ideas for the comic and finding that grifting made him more money. I guess you really can see some of the shift in reading the more recent books, which is sad.