Sure, you can move a mountain in 3-6 months, I've seen such people. Most of them will move the mountain to a wrong place, and won't stay to help bring it back at the desired one. They will just go, leaving chaos back, totally unaware of the mess they created. Or they will move the mountain to the correct place, but will do it in such a way, that no-one is able to maintain, improve, or fix the mountain.
Leaving before a year or two, means you never owned your mistakes. You never tweaked your engineering intuition for teamwork, reliability, or maintainability.
Hey, you might be brilliant, but that's not what engineering is about.