How many of you have actually used one of those extra buttons that are sewed into the inside of garments? (If you don't buy garments with buttons, this is not for you.)
Let's just say there's one of you out there that has used one of those extra buttons. So, let's do the math - that's .000000000000001% of all extra buttons are ever used? Most of those buttons survive the garment they are meant to repair or end up in the back of a drawer somewhere.
Instead, we should have some sort of button registry. When you need a replacement button, you can just scan a bar code from the garment and someone will mail you the dang thing. Just think of the massive numbers of wasted buttons we could save!
Someday, buttons will have RFID technology and will sense when they fall off and a new one will just show up.
Even better, they will be self-sewing.
(This is exactly why Velcro was invented.)