I asked a fireman about sweeping up and throwing away perfectly good fittings and wirenuts at the end of the day.
He told me that the guys cost him more than $1 a minute and he's lose money if they stopping working to pick up something they dropped or sit there sorting for the last part of the shift.
The guys at the big box stores probably just do what the boss tells them and throws everything away.
Even when there's a bin for 'misplaced parts' at Menards I suspect they just pitch everything out when the bin starts to get full instead of sorting it back into the right bins.
