No, it's not really normal, as a few posters have said. Most people 55 or over would have parents late 70s or older. And they have either lost their parents already, or their parents are in care homes or early stages (or later stages) of dementia. Or they are physically disabled, and unable to do some basic everyday tasks themselves, and/or they can't drive etc, and/or they have carers in several times a day.
I think for every person in their late 70s/early 80s and older who is living independently, driving themselves about, and living alone and doing everything for themselves, there is probably another six or seven dependent on their middle-aged adult children and carers and neighbours to help them with stuff. This is purely anecdata before anyone goes off on one. Based on people I know.
The vast majority of women I know over 75, have never been able to drive, and even though many men can (in that age group,) they are unable to do other things on their own (life admin/housework/cooking/laundry etc.)
I know a few couples in their late 70s or older, who are fairly independent, but not many. Most people I know past late 70s are widowed.
You often get people popping up on threads like this with their stories of how they know dozens of people in their 50s and 60s who have parents in their 80s and 90s who run marathons, backpack around Thailand for weeks on end, still work, jog 7 miles to work and 7 miles back, and take their dogs for 5 mile walks every day, and are in awe at how they can run rings around women half their age.
In real life, most people late 70s or older will not be in great health, and will be dependent on others for many things. Sure, a few will be independent, but it will be just a few.