Cornish daffodils

Just back from a couple of weeks down in Cornwall - wherever you walk you seem to come across huge fields of daffodils. Lovely to look at but it got me thinking - what's in it for the growers? Presumably they can't be sold to supermanrkets now as they already out in flower - are they just allowed to die off till next year. Or is it possible to cut them while still in bud early in the year for sale and then they simply grow again? Didn't think of daffodils as a "cut an come again" crop!  Anyone know the answer?