This is true but also useless. AC synchronous motors cannot be easily substituted for Permanent Magnet DC motors in all use cases. BLDC motors with permanent ma

This is true but also useless. AC synchronous motors cannot be easily substituted for Permanent Magnet DC motors in all use cases. BLDC motors with permanent magnets are drastically more energy dense and are easier to control. We've had AC Synchronous motors for a long time, but there is a reason that cordless drills have only been really good for a decade - BLDC motors. Likewise with drones, hoverboards, etc.