Last week I took part in some gleaning action (actually authorized by the farmer).
The harvesting machinery was still in the field so we got to look how it works.
The machine that first passes chops off the tops, and the next machine pulls them out the ground.
... but it chops off quite a lot off the top that is discarded in the field.
The photo attached shows the worst case I found, others were less bad, but overall a huge amount of edible carrot was still attached to the green bit.
... and I only described the wastage from the carrot top there.
This photo shows a small proportion of the rest that is left behind in the field.
KawaiiPunk 
@nicksellen Also, can't you grow new carrots from the tops afaik.
@kawaiipunk I didn't know that, so maybe all those discards were actually to "seed" the next crop!
.. although I somehow doubt it, the internet tells me you need to get some nice roots to grow first before putting them back into soil
@nicksellen yeh I mean, you can put them in water and the regrow some roots etc as you said.