The argument you’re making works just as well for any other crop. Productive land is the asset and the security, not the corn itself. In fact, growing the damn corn everywhere degrades the soil. We might as well grow wheat, rice, legumes, etc. Besides path-dependence there’s little reason for corn dominance.

Agreed that it's the active land use, not a specific crop, that matters from a food security perspective.

Disagreed otherwise though. Soil degradation is due to people cutting corners to save money. Rice requires significantly more water. Wheat and oats don't have the same shelf life. Legumes are likely comparable but how do they stack up against corn for things like animal feed and chemical feedstock?

The reality is that corn is an extremely practical crop regardless of its lack of political popularity of late.