1. With the current "climate trends," my guess is more people will likely turn to exercising indoors, rather than the other way around.
2. Even if GEnerator gyms (GE-nerator, GEt it?
) may not clear the hurdle at the existing energy prices, they may do so at higher prices. E.g., once the use of carbon, fossil and/or nuclear fuels are more severely regulated. (And I am not necessarily saying that they should be -- only pointing to an apparent "trend.")
3. Must assume peak pricing; not baseload.
4. May be used as a local (residential) backup; e.g. during a blizzard with a blackout, or on the Space Station or the Lunar Base -- those times when the price of energy is infinite.