Ugh, that's so frustrating! I've seen this exact thing happen at my local grocery store and the gas station. It feels like a lot of places just set those stations up for show and then completely forget about them. It really does make you question how much they actually care about basic cleanliness, not just for clients but for their own staff too. Once you notice it in one spot, you start seeing empty dispensers everywhere and it drives you nuts.
Actually, my grocery store is pretty good about keeping theirs filled. Maybe it depends on who manages the place? The one by me has a guy who checks them every morning, I see him doing it.