How do people that haven't put away money into their 401k their entire life, live once they're seniors?

Title says it all. I'm not asking for myself as I've been shoveling money away since I was 20 years old. But I'm 45 now and am on track to retire decently but it has me wondering what people do that haven't put away dough for their golden years. I know 50 year olds that have nothing and are living paycheck to paycheck already. Social Security only gets you so far. I worry about some of my family and friends.How do you teach elders the importance of retirement?