You can’t stop coming up with nonsense reasons for why you don’t like miles per hour. Do you not see that there are two  metrics which work together?  One is a static number based on EPA ratings for when you don’t yet know where you are going or how fast.  This is like your miles per gallon number given by the EPA. Familiar? Then there is range based on where you are actually navigating to. For this Tesla takes into account not only terrain but also temperatures and wind direction. Highly accurate and just refreshed via over the air update. 
Obviously the miles per hour stat also takes into account the cars economy such as battery and motor efficiency. Something you wish to avoid at all costs. I get that.  No matter how much you try some will realize this is all about time and distance. Not to mention performance. Clearly areas which 800 volts can’t overcome but we are amused by the word salad.