The electric motor is all about creating an inexpensive conversion of electrical energy into mechanical energy possible. Being the “cheapest” often overrules being the “most cost effective” or “most efficient”. If the mechanism is cheap enough, it’s energy cost over time may not be a major consideration. Being the “most efficient” usually costs a lot more, so this is not a driver either.
Let me explain these last two issues. Being cost effective can be relative. If we apply a cheap fan and motor assembly in an application that moves air, the operating cost per year may be so small that it is not considered in the purchase decision. On the other hand, if you are pushing air through a cooling tower for a commercial building or a large chemical process heat exchanger, the cost of hundreds of horsepower per year is very significant and people pay attention to it.
Being efficient is a very difficult thing to get at, only because we tend to define efficiency in terms of the equipment itself, unconnected to a load, which is totally misleading. Everything about the motor needs to be defined by the application. What you find out is that many, if not most, motors are mis-applied to some degree. This is because electric motors are generally produced as the average solution to a range of applications unless they are being produced by the hundred-thousands for a specific requirement. Disk drive motors are still the best example, for however much longer we are going to have disk drives.
DC motors have very high efficiency numbers, but only in a narrow operating range. So over the entire time that the motor is operating, it may be running at 50-60% efficiency much of the time and 90% efficiency only a fraction of the time. This is not obvious to most people who use electric motors. The same is notoriously true for AC motors which run only at a single speed. In order to adjust the airflow of a large fan, dampers are used which is like regulating the speed of your car from the brake pedal. The widespread use of variable frequency electronics with AC motors seeks to regulate the speed of the venerable AC motor so that energy is not wasted needlessly on the load. Efficiency has very little to do with it.
So the value of legislating a mandate of higher efficiency in electric motors is really minimal. It’s not a bad idea per se, it’s just that it is ineffective at getting to the root of the problem and fixing it. It would be just as useless to pass a law that says every AC motor must have an inverter on it. They will if there is sufficient economic benefit, let the “invisible hand” of economics do it’s job!