Yes getting older presents a few challenges. I'm lucky that (heading into my eighth decade in a couple of years - wow) I can still start and ride and maneuver bikes around, and get a lot of my enjoyment from researching and fiddling in the shed. I have to admit that I do lots more riding on my ebike than I do on old bikes these days, and I do the riding off road to minimise the chances of being cleaned up by increasingly dangerous traffic.
I was going to suggest starter rollers as a solution to your starting problem, but getting the bike on and off the rollers has so many opportunities for disaster that it might be best avoided.
With new knees, have you considered an ebike? If you have low-traffic places to ride near home it's great fun, and - if what I've read is correct - good for knees and general health. Mobility is such an important part of our lives.
Must be frustrating, though, looking at the that little Fanny B... dream machine!
Leon