First of all, an essential way to be in a fine financial position in your fifties (when the tire starts to hit the pavement and retirement may be hitting the horizon!) is to marry well and avoid divorce. This was not mentioned, and IMO is very important. The people I know in bad shape managed their lives pretty well except for losing big in divorces.
I'm glad your kids are out of college--have you seen how tuition has gone up recently? When I was in college, many people worked their way through and emerged debt-free. That's not within reach these days. The hikes in tuition, are, IMO also, a huge fraud.
And the academics I know have good insurance and other nice bennies--one reason why everyone wants to be a professor.
We have seven children...........three in college right now. Two oldest graduate this year..........and both debt free, and they put themselves through school. Tuition, books, living expenses, you name it. Not a dime of debt.
One did it by holding down two or three jobs at a time, yet maintains an amazingly high GPA in a very rugged major. The other worked a job and had help from Uncle Sam (he's in the National Guard, plus did the Army ROTC thing, etc.).
It IS do-able. I couldn't be more proud of these kids, and the fact that THEY did it gives them immeasurable pride as well.
Their degrees plus zero debt......not a bad way to start one's career. :)