RC aircraft have been flying for years, with accidents. They have been flown mostly by responsible educated operators. The increased technology on "personal" drones to fly basically unaided, just go there! Increases the risk to joe citizen. Liability concerns will follow, you can't squeeze bold from a turnip.
Commercial operation exposes a business to liability risks and that business should incorporate fail safe technology to safely land a drone of a control link is lost.
Military drones range from hand launched Raven to full scale, predator, reaper and Global Hawk. Yes they do crash, just as manned aircraft have. Military incorporates many fail safe procedures and pre launch inspections and in flight monitor of aircraft systems.
Most commercial applications with drones should be low altitude and within line of sight of the operator. Extend out to FPV and you are extending the reach of radio frequency and susceptibility to jamming or interference.
Flying a drone above apx 500ft AGL , or within airport traffic areas, requires The same "see and avoid" capability that GA requires. This will be hard to accomplish without everyone on an ADSB type system with a recieve and display capability, not just ADSB-out.