I was already at the length limit in >>10986064
but I have a few more things to point out. First, the additional mass being allowed for "everything else" is almost certainly not enough in either case. Second, your 1 kW/kg figure for a fuel-burning engine is way low. Car engines easily go past 2 kW/kg, and that's with 4-stroke engines. >The problem with people like you is that you think in black and white terms of efficiency. "if it's not max efficient it's useless"
The problem with you is that, as has been amply demonstrated, you're talking out of your ass and willing to sacrifice safety in the name of "practicality" in the hopes that automation will magically make everything work.
I on the other hand look at VTOL aircraft, see that efficiency is already a major limiting factor in technology adoption, and conclude that using options which make that problem even worse are unlikely to lead to mass-market adoption of the technology. That plus a startup is probably a great way to separate gullible boomer investors from their money though. >Electric multirotors are easy as shit to put together and fly.
The main reasons quadrotors are so popular for drones are:
1) Simplicity to an extent that is only really necessary for cheap crap and COTS projects
2) There isn't much size constraint for small drones
3) Very powerful attitude control which is useful for extreme angular (but not positional) stability as a sensor platform, or for high maneuverability aerobatics
4) If you crash it at low speed and it doesn't fall too far there's a good chance that you only need to replace a rotor or two. This is mostly because of scaling laws and will not work at large sizes. Also a rotor failure on a quadrotor that can fly people around is still quite capable of cutting lots of people in half so fixing the vehicle cheaply is a secondary concern at that point.
5) People use them for applications that don't require much payload
6) They don't need to get beyond line of sight