Sorry, I just found the characters to be very one-dimensional/shallow. Malcom is about the most "human" in the series. Granted, I have met many actual people who I felt were equally shallow, but between you and me, I wouldn't want to stay on their ship with them, and if I was forced to, I would spend my time elbow deep in engine with the engineer girl.
As for the "resource depletion" angle; I remind you how very primitive many of the planets in the system are. Most are 1800s level of technological advancement, which would be a massive contraction from what they would have landed with, and this is because of the lack of resource allocation and development assistance from the federation. Granted, the backdrop is that many of these worlds were independent just 15 years prior, so it makes sense that they would have some degree of backward drift vis-a-vis the federation, but not THAT significantly. Especially when there are thriving industries on those same planets. (For example, the ceramic raw material industry.)
We are also talking about a series that actively terraformed an entire star system. That is not a small undertaking. If you have the technology to make alien worlds habitable, you have the technology to fix the earth. I get that it is handwavium to set the scene, but for god's sake, Buck Rogers in the 24th century depicted "what happened to the earth" better than this series did. What gets my choad in a snarl the most though, is the choice of verbiage there. "It got used up; so we moved!" which implies "So we can use them up too, because we did not learn our lesson!" Better would have been "We destroyed the earth, and had to move" or something similar-- something that acknowledges that the action was catastrophically wasteful and shortsighted. But no. "It's perfectly normal human behavior to just trash up a planet, then move."
Meh.