I can't speak as much for America but I know the economic situation in the UK is quite grim. I think in the future any business venture would have to take into account the sure bets. I know several privately owned gyms in the area who have closed down in the last decade as more and more large company gyms open up and inevitably the young fickle clientelle who will bring in the majority of your custom gravitate towards them rather than privately owned ones.
I have thought about opening a gym and like you I have thought about it for the clientelle that you mentioned, but you have to remember that 'we' as in people who post on sensible forums and use sensible routines are in the minority. We are pretty much a fringe group, the market there seems too unstable for a business.
I think in the future, especially thinking long-term as the economic situation in the west worsens the sure bets will ultimately be the only ones worth looking at... land and metal.