My checking account (and the checking account of the majority of Americans) isn’t measured in intervals anywhere close to 10 years.

The reason perfectly rational people like having a cushion in their checking account is that rent payments don’t care about 10 year historic trends; they’re just due when they’re due.

I’m sure there’s a decent collection of people here with enough disposal income that the idea of just having all their capital invested sounds lovely. But we’re inside a bubble here.