A drone that loses an engine falls out of the sky and lands on top of anything that is below it, and as of right now, there are no evasive maneuvers that can be executed. Especially for drones that are being used to record large public gatherings, things like multiple engines or parachutes should be absolutely mandatory, at least by the organizers of the event.
Needless to say, I'd bet it'll take one or two insurance claims until they are.
To my knowledge, no commonly sold cars are exclusively drive-by-wire for the braking system. If you lose all control in a car, you can turn off the ignition and forceful application of the brakes allows you to stop, even if you lose the power assistance.
By contrast, the most common failure mode for a drone in the air is... it falls out of the sky. That's pretty much the long and the short of it. There is good reason that flying objects should be held to a higher standard of safety.
I even suppose that parachutes or stability with 1-2 engines lost might not be "mandatory". The cost of insurance of unequipped craft flying on a major event would be so high that nobody would even try that.
Unfortunately, currently we probably make do with a few less nines on all these items.