I suppose it boils down to whether Entain can continue to provide enough dog racing to fulfil the needs of their customers.
As far as I know they also run Crayford, Romford and Hove. Having worked for Ladbrokes many years ago my understanding was that they kept the tracks in their ownership (in those days just Crayford and Monmore - Romford and Hove were Coral) to give them more control over the dog racing product in the betting shops.