This. But instead of a physical biodome, why not consider Vril energy as a form of "cover" for Shangri-la? We know that Element 115 is capable of displacing certain things throughout time AND space, ignoring any space-time continuum laws. If Vril is very similar to the attributes (effects) of 115, wouldn't it be equally possible to have an Earth-terrain map enclosed in a sustainable biodome while being transported to Mars? I would believe so. Hence, why the map is still lush. Let's not forget that a 115 meteorite hit the temple, which could further the effects of time and location displacement.
I admit I was always an advocate for the area being settled on Earth versus Mars, but over time it started to make logical sense why Shang could potentially be displaced on Mars.
But why?? It makes no sense as to why it would be on Mars. Literally the only evidence is the always trolling jimmy zielinski saying something about the "shangri-la mountains" and some how we find ourselves here now with no additional evidence or indication why it would be anywhere other than earth, yet people still remain adamant about its position on Mars. There are just too many other special circumstances that would have to take place to make it even remotely believable that its on mars, but there is no real evidence of any of those things (like a biodome, millions of years in the past, etc...)
:edit: basically, the way i look at it, until there is some other direct in-game evidence found post shangri-la that supports this theory, then I simply don't subscribe to it