Ok, the propagators might have been the dominant species in the past of the game , but species do not evolve in a matter that their entire body image changes making that irrational and irrelevant.
That's exactly the point. Future's theories are full of statements like that, which are irrational and irrelevant. Unfortunately, Future is immune to anything with logic in it, which is why his topics keep on coming, long after stuff like that has been stated.

And on the topic of his theory, why do yu think that the "beautiful" color check was in the game?
How about the obvious reason: so that the Esthar technicians in charge of maintaining the camouflage hiding Esthar could check if the system was running smoothly. It's really that simple. Of course, it was really put in there more so as to reaffirm the revelation that Esthar was hidden by a complicated camouflage wall, set to showing an empty landscape instead of the huge metropolis really present.