[jiggy2011]

The extra that you have to pay somebody to compensate for the lack of say gym services could well be substantially more than it costs a larger company to deliver gym services themselves.

Consider that a gym membership might cost $50/month at a private gym because the gym needs to make a profit. There is also dead loss because of time travelling between work and the gym.

A company might well be able to provide on site gym services to employees at a much cheaper rate, especially if they already have space that is underutilised, they don't need it to be profitable and the facilities are so close that employees can just work out during their lunch break.

So with everything factored in you might be comparing $60/month to compensate an employee for a private gym vs $15-20/month with an employer provided gym.

The net result is healthier employees because more of them are likely to use the gym than if it was not provided and it's also a more efficient way to provide gym services if it is used by more than X% of employees.