I think the reason is that no one uses staplers, and yet there's a cupboard of them. Obviously it's not just staplers, there's loads of stationery, but why? A few pens and some notebooks is all that actually gets used.
So the staplers continue to sit in cupboards, unused. They've already been bought, so how is Google saving money? Selling the staplers? I bet they were just thrown in the bin. How wasteful.
Because they probably hired a third party supplier that gets money every month to make sure stationary cupboards are filled.
I love staplers. I love playing with them and the rows of staples. My favorite unused-in-decades office accessory that some offices still stock is the staple remover, it's a great little (sometimes painful) fidget.