I think we all need to aim for an active life rather than doing exercise if we don’t want to or can’t. When we talk about relatives that are of previous generations who never exercised, they were likely active in ways we just aren’t.
im a bit disabled (spinal issues and I have just had a big hip operation) so I concede I probably take some short cuts. However, I get the shopping delivered, we have a dishwasher, washing machine and tumble dryer. I haven’t ironed in years. We have a lightweight Dyson (erm and a cleaner and window cleaner). We have a relatively low maintenance garden, though needs mowing and weeding and we do have an allotment.
if we go back to the 40s to 80s running a home and garden was a lot more active and people often only had one car, if that in some cases! I’ve had several older relatives who never learnt to drive or never saw the need to run a car.
That hidden level of activity I think then stood them in good stead in later life. Many of us grew up with parents who didn’t exercise so we didn’t have that modelled to us. However, our parents and grandparents were active and so managed without it. Then life changed and we now need to specifically exercise or look for opportunities to increase our activity across the day / week.
Add in bad experiences with school PE and I can see that people are going to have more unwell later life unless they build the bone density, mobility and muscle to see them through.