In part that’s because combustion engines scale down extremely poorly (they lose efficiency like mad… a micro turbine gets like 5% efficiency whereas a full siz

In part that’s because combustion engines scale down extremely poorly (they lose efficiency like mad… a micro turbine gets like 5% efficiency whereas a full sized turbine gets upward of 30%) and have high complexity. They’re also difficult to throttle on command with high responsiveness (hence the swashplate). Electric motors are far better suited to distributed lift concepts. That’s a huge reason why existing vertical lift doesn’t use multiple rotors. Electric motors using high energy magnets, modern solid state power controllers, and modern batteries are only just now becoming available & only now are they starting to impact the aviation trade space.