Sales, marketing, operations and customer support would all need to add people as the size of your customer base grows, not just as you start adding new functionality.
Seriously though. I toured a startup nearby me and they literally had a massage therapist, barber, therapist, barista, and numerous other service workers employed and working at least 9-5 every day serving the ~50 employees, 30 of which were sales, 10 engineers, and 10 executives.
As far as I could tell nobody used these perks that day. A guy even made his own coffee at his desk.
Unless the company was swimming in cash a la Google or Apple, I would feel weird using services like those. Even if they had the money, I would prefer to just be paid more.
I imagine that due to economies of scale you'd be getting more value out of those services than you would from the equivalent cost to the company in pay. But that's only the case if you actually use the services and you would've paid for them anyways if they weren't provided.
