Every time I run across this thread's title -- and it's not incorrect -- I think of the limiter function on the cruise control, and wonder why anyone would want to eliminate it. 😄 But I too am wondering about the speed governor at the top end. The controller rolls off speed well below the car's capability; it should easily be able to keep pulling until maximum motor speed (and perhaps when aero drag starts slowing acceleration). I'm quite certain BMW chose to roll it off and limit speed to 150 km/h to prevent us from killing the battery.
There are a number of reasons to limit a vehicle's top speed. Tire speed rating and aerodynamics of the vehicle come first to mind and the vehicle's market.
EV tires are intended to provide low rolling resistance. While I believe tires intended for EVs could be made to a higher speed rating where's the demand? To fit these tires adds cost and EV makers are fighting EV costs already.
Sure one could fit tires with a higher speed rating but that owner would be an extreme outlier compared to other EV owners.
There is also aerodynamics. As speed increases air flow over/around and even through the car (to cool the ICE engine and running gear) becomes ever more critical. As car top speed goes up cars take on a more aerodynamically friendly shape. This means less cabin space and harder ingress and egress.
Was a pretty easy activity to get into and out of my VW Golf TDi limited to 115mph. Not so easy to get into and out of my Porsche 996 Turbo drag/power limited to a top speed of 189mph.
Allowing the EV motor to spin faster generates more heat. From the increased amount of current flow and from friction. Now one has to provide a way to keep the temperature under control. More cost.
The vast majority of EVs are used for short commutes at relatively low speeds. Why burden every car with the cost to support a higher top speed when that is not what the EV market wants?
And the effect on the EV battery has to be considered. What effect would driving at max V have on the battery besides just draining it faster.
Saw a video of a Tesla 3 being used at Pike's Peak. The car was very quick. But it was noted that despite a full charge after the run there was a noticeable drop off in performance. Just calling on the battery to deliver the electrical power during the run up the mountain had a negative effect on the battery.