Stress is relative to your own personal conditions. It's not absolute. A tech executive might have a nice house and financial security, but if he's working 80 hours/week under intense pressure to meet some deadline, that's still stressful. Nobody wants to be perceived as a failure at work, even if their personal financial consequences for failure are minimal.

Your argument seems to imply it's impossible to feel stress if you're comfortable in life. Even the poorest Americans can count on access to food, clean running water, electricity, internet, etc. For most of humanity's existence, and still today in some parts of the world, these would be considered enormous luxuries, so anyone with access to them would be seen as extremely comfortable in life. Clearly though, people can still be stressed out despite having access to these sorts of things that most of history would consider luxurious.

Stress is relative, not absolute.