And then add in all of the other e-bike parts including motors, batteries, throttles, speed controllers, etc. All of these parts are mass-produced in China. They simply aren’t available in the US and no one is designing them or manufacturing them. The US would likely have to start by reverse engineering the Chinese products and learning how they produce them. How’s that for irony?
E-bikes mostly use motors and battery options from a few major suppliers: Bosch, Yamaha, Shimano, and Brose. A few other brands exist, but are less reliable or powerful. Some, like the Yamaha system, have more torque and others are quieter. But generally all four make good options. Look for motor output (in watts) which will give you an idea of total power. But watt hours (Wh) is perhaps a better figure to use—it takes into account battery output and life to give a truer reflection of power.