Mars lost its atmosphere because Mars does not have enough gravity to have held it. Over time, there was a gradual loss of the atmosphere, including water, to space...Perhaps Jupiter stole some of it.

The relevance of the quote from Manilius is that Mars began in a certain way (size, distance from the Sun, proximity to Jupiter, chemical composition, etc) that was different from Earth's beginning. Therefore, having a different beginning, the end is also different, being inherent in the beginning.

Our moon has no atmosphere, no water, and is geologically dead. Our planet has a thick atmosphere, huge seas, and is geologically dynamic. Their beginnings were different; the course of their "lives" is therefore different. This also applies to each and every human on Earth.