It's not about tech saavy. It's about the slow decay that is life. You could be Bob Metcalf, Doug Englebart, and Marty Cooper all wrapped up into one, but none of that will suffice to overcome the challenges of the aging body.
As someone in my late 50s, with friends around the same age, our only accessibility issue is an occasional need for reading glasses.
You've lived fortunate lives if you've never experienced mobility or perception issues sufficient to interfere with daily life, even temporarily. Not a single broken leg, black eye, torn ligament, not even a sprained ankle. Never experienced the joy and trails of pregnancy.
Sure I've been injured, but that's not due to an "aging body." I got injuries in my 20s, but I don't attribute that to aging. Most people wouldn't put pregnancy in that category either.
Besides, a sprained ankle or whatever doesn't much affect your ability to use tech.
You could be in your 50s and have used computer tech since your youth in the 80s and still hate the current UI holy war against scrollbars and contrast.