In such a situation, the airline does make a refund on the unused portion of a ticket ; what does happen though is that the one way fare is charged for the outbound and then the rest is refunded

Looking at current time of year, the one way fare currently starts at around £3,331 , so the refund amount would be around GBP564, so GBP580 seems correct and would indicate that there is no fee being charged by Emirates or the travel agent but is giving a full refund of the return flight

There is no greed , just a business transaction calculating based on the standard method of calculating fares