I can't find it, but I think pg also said something like "when you're 20 if you're not doing bad you feel good. When you're 50 if you're not doing good you feel bad."
Which seems like common sense. A 50yo has fewer years to with to save up for any retirement, they face age discrimination, increasing health issues, etc. A 20yo has many years to work and pivot on case of setbacks, less age discrimination, usually fewer health issues.