As jwz pointed out, at http://www.jwz.org/blog/2008/05/the-collected-jwz-bicycle-wi... , SF "is only 7 miles across. Nothing is as far away as you think it is."
I've never lived in SF. I have bike commuted in a city with hills. Low gears, go slow, and your leg muscles quickly build up to it.
Update: dalke above wrote "I thought it was going to end up that the author decided to ride a bike around the city. The starship of the past is still a starship." You seemed to ask for clarification about when you talked about a starship from the past. You didn't. dalke did. I clarified what he meant. You should reread this thread, take a step back and climb out of your own head. Read.
In reading the piece, I thought it would break the parallel construction by joining the present back to the past. It didn't. But it didn't explain why those couldn't be connected other than "We aren’t children anymore and things cost money."
I took that line to mean that the author recognized a need to separate the worlds of childhood and adulthood. I didn't like this explanation because bicycles do cost money. Eg, in the jwz link I posted, jwz points out that bicycles will get stolen, so use cheap bikes and don't get attached to it. If the mean time between thefts is 100 trips, then that's about $5/trip, or well below the cost of a car, taxi, and Uber.