How to deal with changes if inspiration?

I’m currently working on a Mediterranean - French Riviera inspired city and had so much motivation and inspiration. However, recently I just watched the new Spider Man film and now really want to work on a New York inspired city instead. The problem is that this always happens to me. I enjoy trying to make the city as realistic as possible so by the time I get an idea for a new city I only have a small part of the old city finished. I do want to one day be able to “complete” a city, but I can never get to this point before my inspiration changes. How do you guys deal with this?