[KensRedZed]

In simple terms. The controller converts DC power (2-wires) to AC power (3-wires). The windings are stationary, and the magnets spin around or inside the windings. It's been in the RC aircraft hobby for many years. All brushless motors have an amazing power to weight ratio. You barely got 60% efficiency for a regular brushed motor. You can get 90% efficiency with a brushless. That makes a huge difference in power and flight times for RC planes.

The friction of the brushes really slow down a regular DC motor. They also create gobs of heat. It's not the best way to transfer power.

They have high dollar DC brushless motors too. But only for industrial use.