'Rich, Broke, or Dead' made me realize that I was more likely to die early into retirement then I was to run out of money. In my case that made me realize that I'm not using my 30s effectively. I really like this visualization.
No Medicare, so you still need to buy insurance and pay for out of pocket maximums, and you are less and less employable for jobs that offer decent subsidized health insurance. Also, unless you qualify for significant ACA subsidies, premiums are going to be more than $1k per month per person.
And at the same time, most people will be getting their Type 2 Diabetes/Hypertension/Thyroid/etc diagnosis so their chronic medicines start.
If a married couple can both cross the age 65 line before hitting a big healthcare event, then they will probably be OK, but that is far from a guarantee.
This is obviously a personal anecdote and ultra variable-dependent but my entire elementary school -> middle school -> high school friendbase hang out exclusively in Discord playing video games/watching sporting events digitally instead of in person. I wonder how widespread this is.