You're on the right track. Often times these gyms use median income when deciding where to expand. With Jersey City having such a large population, the median income is 41k. We know most people downtown make much more than that if rent in buildings is upwards of 4k in a high-rise at this point. Seems like a lot of these large corporate gyms have to catch up.

Space is probably also a concern, but I can't see why one of these developers won't come to an agreement for a large commercial gym before they build. Seems like an easy way to make a ton of $ off first-floor commercial.