It's the larger office/business grade MFP's that have hard drives in them, bigger HPs, Canon ImageRunner class, etc. Units that are like....the size of your oven, and larger. //refer to the video they show. Those aren't the little 70 dollar HP or Brother AIW units that homes and small offices may have.
Most business lease or have contracts with larger companies that service/replace these units, such as Copytex/Flotech, Ikon, etc. They do "cleanse" the hardware cycled back in on lease renewals. It's the cheaper places that practice the lazy, shifty way of reselling used hardware.
It's not a matter of speed...the drives are used for as a sort of swap file, and even old slow PATA drives from years ago have way more than enough speed for copiers.