Even if it is possible, would it not only double capacity if segregated mode was abandoned?
How would the prospect of permanent mixed mode go down with flightpath residents?
Well technically it's neither segregated mode (separate runways for arrivals and departures) nor mixed mode (interspersed arrivals and departures on the same runway).
In fact I don't think a term has ever been invented for landing and taking off simultaneously on the same runway - "aircraft carrier mode", perhaps ?