What we still lack to attain maximum efficiency?

From early days there were three resistances which hinder the path of attaining the maximum efficiency.Other tgan engine power its resistance which offer full control over efficiency.Road resistance,air resistance and grade resistance.Grade resistance is not considered as we mostly use flat surfaces.Now only air and road resistance make a opposition to attain max efficiency.There is a fact that "when a vehicle is moving at a speed more than 80km/h then half of the fuel were consumed for overcoming the air resistance.When mag lev trains were invented it reduced road redistance to a high extent.Now hyperloop has been invented to eliminate air resistance.So now all the resistances were overcomed by new techniques.I want to know whether this is the maximum speed to be attained by hyperloop trains or there is any other way?Is this the max efficiency to be attained?