It is a pretty simplified view.

I wrote an electric vehicle power / efficiency / range estimation program back in college when I was very into building electric bikes. (More advanced version of the ebikes.ca calculator for an example). There were a whole lot of parameters that went into actually estimating the performance, but the general rule of thumb was rolling resistance is pretty much worth ignoring (for efficiency) until you have spent time optimizing aero and drivetrain losses.

It was pretty damn close to real world measurements.

I'm going to use rules of thumb rather than exactly calculating things for a colloquial conversation online.