It depends on your definition of elites. "Deep state" and "drain the swamp" is about attacking government elites but the same movement promotes less regulation and lower taxes for business elites.
It doesn't matter who the elites are; it only matters that some notion of them exists. The key to populism is the claim that some political platform (left, right, religious or secular) represents the manifest will of the people in its entirety, and that any opposition to that platform is corrupt or elite-driven. If you're looking to understand the term by its opposition, the antonym of "populism" is "pluralism".