This really made staying independent possible, for the months it took before I could walk properly. Sure it was slower to drive to the supermarket & park underground there, instead of walking... but much quicker than waiting for someone else to have time to help.
I agree that solutions other than a traditional car would be possible. But right now, thinking through other places I've lived fine without a car, they would all have been hell.
After the first week I broke down and just took cabs everywhere. Perfectly practical, but only when somebody else (in this case, my employer) is paying for it.
In defence of the transit, it has to be said that (in a city that size) those cabs could not work without it. The roads are only passable because 90% of people aren't on them.
Which is to say, the fares have to be out of reach (as a daily expense) for > 90% of people. I imagine most employers would balk at the cost of catching cabs everywhere in Oslo.
What helped me a lot was getting an e-bike that I'm able to cruise around town at 20mph (32kph) in. I understand that this particular solution doesn't apply to you, since arthritis is triggered by joint movement, whereas my pain is triggered by impact on the damaged foot and ankle (and e-biking is low impact).
But this experience got me thinking a lot about small electric vehicles.
One could imagine a city center where most people walk or bike, and people with a medical permit could drive around in speed-limited, electric golf carts, which are fairly compatible with pedestrian-only areas. Perhaps the city itself would staff the golf carts with drivers who were summonable via app.
So people like us could drive to a parking garage on the outskirts of the city center, and then there would either be rentable golf carts at the garage, or golf carts able to be summoned to go into the city center.