This is anecdotal, but a lot of my peers who graduated around 2009 are living way below their means because they know it's realistic to be hit by a major stock

This is anecdotal, but a lot of my peers who graduated around 2009 are living way below their means because they know it's realistic to be hit by a major stock market drop along with losing their job, which might not be recovered for months, if not years. So it truly could be a "delayed" effect where a lot of the upper middle class can ride it out 6 months - 2 years, but then it really hits.