As a real pilot plus a drone flyer, I can tell you that my aircraft (that I sit in and fly) is in my opinion, far more of a reliable build than my drone is. Plus, all flying things that people sit in, can actually glide down should there be an engine failure, though the success of a safe landing depends on the pilot's concern for safe flying practices and ability/amount of recent training in emergency procedures he/she has had.
If my aircraft has an engine failure, I am going down with the craft and will be able to glide it to a safe landing, because I have trained for that and I have trained others many times (I used to be flight instructor) so the reality of an engine out is something that has been covered many, many times in the past. Many pilots think the prop is there just to keep them cool, since the moment it stops a lot of pilots immediately begin to sweat profusely. And I practice safe flight by making sure I always fly over areas that will allow me to glide down to a safe landing spot, should the engine ever fail.
Too many pilots think like car owners, that their engine will never stop and therefore, allow themselves to fly over terrain that would not allow a safe outcome if they had to put it down in an engine out situation. Part of your flight training is to always have a place in mind as you fly, either, ahead or to the side of you and of course not to forget what you just flew over that is now behind you, that you can land your aircraft in, should there ever be an engine out situation.
Flying my drone, if the engine stops, it is just dropping out of the sky, no one flying a drone will have control of it because it is not like a helicopter, so the pilot cannot autorotate to a safe landing. It will just drop and hit what ever it falls to on the ground. Therefore, no amount of training or real pilot ratings will ever make you any better than any other drone flyer, should that engine fail. That is why so many suggest not flying over people, not as drone police, as some have suggested here, but simply as good pilot judgement and safe flying practice.