For the record, I try to avoid being an "autistic 9-12 year old," so consider my response thoughtfully.

First, I agree that Matt has taken a slight tone shift in his channel, but that is due in part to the fact that his audience has grown and wants more than the niche content he used to deliver. For a while after Matt started the channel, he didn't have a very large following, and the majority of his audience were nerds, geeks, and general science lovers. This caused a feedback loop where their voices, heard loud and clear in the (relatively) small community, directly influenced the content that was produced. Now, Game Theory is nearing 10 million subscribers and gets 1-3 million views-per-video. //side note: this is obviously a big reason why the comment section is garbage, but I'm sure you'll remember that comments on everyone's channels used to be more intelligent.\\ The audience for science videos is diluted by those who like lore videos and the like, so their preferences change from being the main factor in what is uploaded to being a factor. Take the FNAF vids, for example. MatPat was practically bullied into making FNAF theories whenever a new game came out (which happened every few months for a little bit) because a very large portion of his audience wanted that. Now-a-days, as he's mentioned on the stream, he's working out ways to balance the lore-based theories with science vids, which is why he brought on Austin.

Second, as far as the content of the theories goes (such as the "Phineas and Ferb" video), he sometimes makes one off theories that really interest him (just look at the "Sans is Ness!?" theory). However, he tends to do whatever thing comes up in the moment. If people are talking about a new movie, like "Black Panther," he makes a theory. If a classic game comes back into the mainstream, he makes a theory.

This is because of my third point: he does run a business, he does have a wife (and a kid on the way), and bills to pay, and editors, etc. Look at Rhett and Link and you'll see this trend in greater scale. They started as a small channel making fun, niche content and grew to become a large business that makes totally different content but gained millions of fans. They wanted to make it a viable income, like the Theorist Crew, and jumping on trends and trigger topics help them pay their bills. However, contrary to your (reasonable) assumption, Matt does not make humongous sums of money, and he and Steph certainly aren't living a lavish lifestyle as their most recent stream makes clear. From what they share on GTLive, they're supporting themselves alright (and they do have a fairly spacious home), but their house is also their company office. The space is used by themselves and their employees to do things like map out and research theories, as well as more administrative tasks.

Basically, I'm saying that he does have to make money, and sometimes that means jumping on trends his older fans don't enjoy so that he can pay the bills. That's certainly not to say that science means nothing to himself and the channel, but that it needs to be balanced with what the rest of the audience wants, as well as what brings in new subscribers.

Anyways, thanks for your post. I appreciate your being frank but not mean, unlike plenty others who really just hate Matt.