Small businesses basically did nothing in preparation [for Y2K], and they still had a fair amount of dependence on date-dependent programs

The smaller the business, the less likely they are to have their own software that's not simply a database or spreadsheet, managed in say, a Microsoft product. The smaller the business, the less likely that anything automated is relying on correct date calculations.

These at least would have been strong mitigating factors.

[Edit: also, even industry-specific programs would likely be fixed by the manufacturer. For example, most of the real-estate software produced by the company I worked for in the 80's and 90's was Y2K-ready since before 1985.]