As a real estate broker, I see this all the time. As people get older, it's harder to get up the stairs, plus a certain size requires maintenance and heating/cooling costs are also tied to the the square footage of the property.
There's a certain amount of people on here who hate condos. I don't run into as many people in real life. You just have to know what you're getting into. You always get a copy of the condo budget and rules/regulations, so you can examine them for yourself. I think what many people on here don't get is that the HOA fees are fees that you would pay yourself if you lived in a single family. Things like heating, hot water, maintenance, insurance, water/sewer, reserves. Those are all in the budget. I've seen a lot and basically it usually works out to about $50 a month per unit for a management company to handle the books and take care of things. The place where you can run into problems with an HOA would be a small one where you would have to get along with your neighbors. In a larger HOA, they're usually professionally managed and tend to have less issues.
Remember, just like driving where you just hear of those spectacular car crashes, condos are the same thing, many people buy them with no issues. People on here like to go on and on about the horror stories and take the exception for the rule.