Italian fascism, i.e. the iconic original fascism, absolutely had corporatism as part of its definition. To their credit, it involved not just business owners and employers but included employees at the table, which is better than American billionaire oligarchy.

It’s not the universal and core definition of fascism but that’s not what I said, it’s an alternate definition which has applied to historical fascist regimes. Fascism is a far right ideology. It’s not just classes and hierarchy or authoritarian government and nationalism, it’s a fuzzy intermingling of many of those things.

The “simple” part of the definition is that it’s a far-right authoritarian regime, which contradicts the oversimplification at the top of this thread.