Mr. Smiley
Member
Because it's based on a very specific photograph of Earth and the icon they made features the clouds from that image in addition to landmass as well as being depicted from a different orientation than usually shown on globes and maps.
It's not an uncomplicated image, and certainly not simpler than Mega Man's helmet, either from an angle (as Georly shows), or head-on, like in the 1-up sprite. Anyone can draw something that looks like Earth, but the Mother icon is a very specific Earth.
It's not matter of complication. I used the wrong wording and leaded to the wrong argument. It was the matter of depth to aesthetically fit with the other images. Before Georly's image, I had thought that Megaman's helmet needed to have such in order to be recognizable without looking weird, but apparently an internet image was enough to throw that into question as it's show from an angle.
The helmet head-on? I don't believe as such without depth but that's probably a matter of perspective.