Dream Theory Is Not Canon And Never Was
So I typical avoid addressing on MatPat and The Game Theorist as a whole directly say for sometimes when I think it is relevant. This is one of those case because MatPat basically created this "theory" and has tried many times to claim it was Scott's original intention. Alongside claiming he got this right and implying Scott changed it because he was right but also because people wouldn't like Dream Theory being correct.| This bit of information has lead to many FNAF Fans themselves believing Dream Theory was the originally intention or is even possibly still canon especially thanks to a misinterpretation of Five Nights At Freddy's VR: Help Wanted. So I'm going to point out the Smoking Gun on why Dream Theory is not only not canon, but was not Scott's original intent for the first 4 games.
So leading up to Five Nights At Freddy's: Ultimate Custom Night Scott made some joke posts about the game by updating the character guides of some characters on Steam, and would later update them, to their correct descriptions. These include.... Nightmare Fredbear “He appears suddenly in your office holding an alarm clock. You have only a moment to press the button and activate the alarm. If you press the button in time, you will awaken in your bed for ten seconds before falling back asleep and continuing the night.” Foxy “He will run into your office when things are looking dire and offer to help you. You can choose one of three ways for him to assist: He can block one door, clear the vents, or add 1% more power to your meter.” Phone Guy “He will call into your office at random, creating a lot of noise and momentarily increasing the aggressiveness of the animatronics. He cannot call, however, if Springtrap is in the vents, because he can't be in two places at the same time.” What is noteworthy is these are all based on old FNAF "theories." Like Foxy being a good guy in Five Nights At Freddy's 1 and is just checking in on you. Alongside the "theory" that phone guy was the killer. These are incorrect theories, and alongside them is Dream Theory even referencing the the alarm clock which MatPat focused on in his "theory." This would seem to imply through these jokes that Dream Theory alongside these other "theories" are not correct.
Scott seems to make a habit of this, as seen in the special tease for the movie Scott released Freddy in Space 3: Chica in Space. This joke game references all kinds of things from the fandom included Adult Theory. In this game there is a boss that is making a joke about Gregory being well a robot.
Finally I would like to note this Five Nights At Freddy's 1: Movie seems to further back this up. The movie makes references hoaxes in it like the Sparky the Dog hoax, and even has William Afton the killer be the Phone Guy in this movie. Alongside it the movie features none other than Dream Theory. So the movie basically contains several "theories" and even hoaxes that were incorrect in the games. Written by Eris