Boredom and wanting to work on something new is probably the biggest driver
I have to disagree with this point. Switching jobs is a very stressful and scary experience. Most people don't want to jeopardize their income without having some very strong motivator. In my experience, the most common reasons someone changes jobs is:
I don't agree with the logic that we cannot focus on two things at the same time. It's like saying, "People focusing on making movies when we have such an immediate problem to address TODAY are delusional and actively endangering the most vulnerable people in the world." or "People focusing on curing fibromyalgia when we have such an immediate problem to address TODAY are delusional and actively endangering the most vulnerable people in the world."
The bottleneck to reversing climate change is not money or manpower, it is politics. We cannot force other people (especially in other countries) to do the right thing for the environment. We can, however, do our best to improve things on our side and pressure others to do so as well. And while we are putting our best effort towards that, we shouldn't stop making art, researching medicine, or even, trying to colonize mars.
Also, the research and development needed to colonize Mars may very well yield scientific discoveries that allow us to reverse climate change. And even if it doesn't, and Earth is ruined despite our best efforts here, we won't have all our eggs in one basket.
My point is, I just do not believe that researching colonization of Mars will do anything to thwart our efforts to improve the Earth. Quite the contrary, it may help those efforts.