It’s possible that you may be running Khan stage 4 for many months and not become a Khan. As @GoldenTiger and @Lion and others have said, the previous stages lay out the foundation for KHAN. Without a good solid foundation, you would be like a weak building that collapses easily from the slightest tremor in the ground.
Ultimately, I think it depends on how close you are to the Archetype of Khan. If you’re very different, then do all the stages.
So far I’ve been on stage 2 for about 4 months. I plan on doing 6 months on stage 2 before I move on. Because my persona is very different than Khan.