Yes, you don't need to be nearly Amazon's size. USPS mail drop box locations are the responsibility of the local postmaster. It's basically a matter of asking

Yes, you don't need to be nearly Amazon's size. USPS mail drop box locations are the responsibility of the local postmaster. It's basically a matter of asking politely and there being enough mail to somewhat justify it. It's not uncommon for large commercial real estate developments (like a new strip mall or an office park) to arrange to have one installed when the facility opens.