Gyms are now closed. The thing about suburbs is that you can be anywhere anytime, thanks to your car and garage space to store bicycles and various recreational things. If I lived in the city, I'd likely have neither and would be bound to my city block (parking isn't cheap there).
You can definitely walk further than your city block! Here in Montreal, I walk a mile to work daily. In summer, I could bike, but there's no reason to.
Another thing is in mixed-use developments, you might not have to go too far. My block is entirely condos, but the next block has a pharmacy and a grocery store, and the block the other way has a grocery store, a few fast food places, and across the street is a rather nice sushi place and a bar. Instead of going to the things, you just live where the things are.
I live in an apartment in downtown Seattle. I store two bikes easily, and use them often for exercise but also to visit farmers markets (when they are open).
