Thanks for sharing your experience Bill.
I was shooting for simplicity here, which is why I didn't go into the details of all possible income sources that could go into your "fixed" income.
E.g., some people have a defined benefit pension. Some have annuities. Some, like you, have significant rental income. However, most people don't have any of those, so their fixed income is at best from Social Security.
For someone like you were 20 years ago, they'd just include their rental income in the F, and they'd be good to go.