It's because it really is irrelevant. Unless they give you height above terrain, it means nothing. Even then, unless you're familiar with the topography of the land, it can mean very little. My antenna is 40 foot above ground. However my elevation, while not bad for 'the area' is bad for my exact area, as everything around me is taller. Found a house we loved, if only it'd been on a mountain, or at least not in depression by a river.
I can run 40 watts, or 100 (only in testing) and my distance is maintained. My next hope is to buy an old tree trimming truck, and turn it in to a tower lol.