There are not enough hours in the day is so true for so many.  The trend that I have been seeing for the last 15 to 20 years is that nobody is home anymore.  Both moms and dads are working now and they are lucky if they can keep their kids at home with a nanny or a babysitter.  Most folks are gone most of their day in the first place for work, so who has time to go to the gym anyway.  Finding 15 minutes of solitude at home is hard enough.  So why not create a home workout program to relax into after work to help unwind.  I bet in the next 5 years we will see home gyms popular selling points to new home developers.