Because there’s no left wing party and the Dems have chosen to disallow left wing candidates, so why register as a dem even if your going to vote Harris?
It’s not like there will ever be a primary for the party not exclusively decided by party donors.
Retirement age for you is 67 with a max 1200/mo in ss, and most pension funds have gone bankrupt. Unless you have a military/federal pension or already have the 2-4 mil needed for “fun” retirement and eol care saved you’re not retiring.
More 70 year olds than ever before are returning to the workforce, and they had everything handed to them.