Housing and healthcare costs are insane. When you're older, you need a lot more healthcare (and you won't have that nice insurance plan you had at your big company job when you were working), and housing keeps getting more expensive, which is a problem if you're on a fixed income. You could move to much cheaper locales (i.e. rural areas), but those are "healthcare deserts" where there's no competent doctors left and hospitals are all closing left and right, plus when you're infirm how exactly do you drive yourself? Living in a walkable city (or any city really) is much more doable when you're older for these practical reasons (less need to drive, healthcare providers close by), but then you can't afford the housing there.