Stress can be for a few days or weeks or months. Burnout is a months and years thing. It's the result of chronic stress. You can just get a mental block and cannot even touch or look at something. It may make you unable to do the work you once did. The mind can shut down for self preservation. Even after years of recovery you may not be the same person.

Which makes a lot of sense considering a lot of Dev shops went from waterfall oriented projects to continual devops. When fallout New Vegas came out, there were only a few MMOs that were selling horse armor. Now that has become the standard for almost all multiplayer games. Every multiplayer game now has its own in-game store to better suck dry addicts and make producers life lazier and easier. And since we're pushing out so many buggy rapid releases, the devs need to keep working to hot fix what traditional ly would have been QAd and improved before release. This is clear to me and I have never worked in a game studio.