Rebbe Dovid Lelover zt'l said: If Korach knew that he can serve Hashem from behind the oven [where the simple Yidden used to sit] and his avodah will be as precious as the avodah of the kohen gadol, he wouldn't have made the machlokes."
According to this explanation, Korach wasn't seeking honor, wealth, or prestige. He was disappointed that he couldn't serve Hashem as well as Aharon HaKohen. "I should be the kohen gadol," he exclaimed. "I want to serve Hashem in the Kodesh HaKedashim. Why must I settle for a secondary avodah?"
And this was his error because his avodas Hashem wasn't at all secondary. Each person can be as great as Aharon HaKohen when he devotes himself to the service Hashem expects from him.
The Gemara (Pesachim 50.) tells that Rav Yosef the son of Reb Yehoshua Ben Levi saw an "upside-down world" (ԀԀԀԀ ԀԀԀԀ ԀԀԀԀԀԀ, ԀԀԀԀԀԀԀ ԀԀԀԀԀ ԀԀԀԀԀԀԀԀԀ ԀԀԀԀԀԀ). Those on top were at the bottom, and those at the bottom were on top. He discovered that the people honored in this world are not so important over there. Simple people who study with mesirus nefesh are honored more in heaven than those who have more time but do not use it fully.