In little photography drones, the asset itself isn't worth enough to put lots of expensive mechanical technology into survivability. To make the leap into human transportation, that will have to come.
Chinooks fly mainly through magick and the Earth rejecting them (as in all hicopleters), but the counter-rotating rotors are essential if no tail rotor is used - and they of course must be fully articulated so that the two rotors can counteract the yaw induced by each rotor's motion. The loss of a rotor on a Chinook is terminal - it cannot fly on one rotor. It can lose a powerplant, as both engines drive the rotor system.
As I mentioned above, if a quad-rotor has gimballed electric motors so that each rotor can apply a degree of sideways force, there's no need for the complicated and expensive articulated rotor heads that helicopters use, and if the gimballing is sufficient then the loss of a motor/rotor could be accommodated. Effectively, the asymmetric rotor becomes a tail-rotor, though with a degree of vertical thrust also. The main advantage of a quad-rotor is its simplicity, and that needs to be maintained if it's to have any advantage over other aerial vehicles.