A drone that can carry 150 Kg of passenger can:
also fall with a hell of a thud, when (not if) the rotors suddenly stop spinning due to any number of possible causes. Even with some sort of "Dead Man" chute arrangement, you still have a heavy payload that is guaranteed to obey the law of gravity, ending up:
(a) stuck on a roof,
(b) in a tree,
(c) on a busy freeway,
(d) all of the above.
Pretty well anywhere other than the intended destination.
And you can bet that the lawyers will be on standby when it does.
And as the ability to hover at the intended destination will be an indispensable requirement, two or more spinning rotors are guaranteed to be present, ready to slice and dice their way through any (in)convenient obstacle(s).