You’re right, the textbook definition is social ownership of the means of production, and “socialized costs” or “public support” would be more precise for what I’m describing. And I don’t think it’s “well-defined and widely agreed-upon.”

Marxists, market socialists, democratic socialists, and libertarian socialists all disagree on what it actually requires, and in everyday US usage it’s commonly used to mean government spending for social programs.

Either way, my point stands: we already collectivize risk and costs for some groups. The real question is who gets that help.