This is one of my faves because it parrallell’s Trey’s relationship with Matt.
Trey/Stan is the “talented” one out of the two and Matt/Kyle is “holding him back”. People often say that Matt doesn’t really do anything, that it is Trey who writes everything etc. (Of course we all know that Matt actually does a whole lot more than just keep Trey company) but what is important to Trey/Stan is doing it all with their best friend. Both Trey and Matt have often said that South Park is the energy between the two of them. First and foremost, South Park is simply the product of a close friendship, and would not exist were it not for their close relationship and the chemistry between them.
“I thought I was having a great time because I was getting signed by managers and, going to big sex and coke parties, but, then I realized, I was having fun because I was doing all that…with my best friend” - Stan
I mean it’s clear that the reason the dialogue between Stan and Kyle seems so genuine here is because it is pretty much how Trey actually feels. And although Matt actually does a whole lot, like take care of the business side of things, arrange and do interviews, make sure the episodes get done on time etc, to Trey it’s all about their friendship. And he could not do it without the support of Matt.
And while we are at it, let’s not forget how friendship has been a running theme through much of their work. It has cropped up on several other occasions in South Park, it is pretty much central to the storyline in Book of Mormon, Baseketball and even Team America.
Basically Trey just really loves his Super BFF.