Realistically speaking, one person can't create an AAA game on their own, even if they have a degree in game design. The resources and workforce needed to develop video games are way beyond what many people may think. Fully dedicated teams work in the development process, and even then, it'd take years for these teams to develop games worthy of claiming the AAA quality title.
Designing and developing a new video game requires vast knowledge in several disciplines, like game programming, 3D modeling, and interactive design, which explains why such games are created by large teams that have members with unique skills and knowledge.
Not to mention, brainstorming ideas can be quite challenging for one person to do, and it's an integral part of creating a top-chart video game that'll appeal to a good number of gamers.