If you look at TV series in general, the vast majority of them are not about the military. So why shouldn't there be more SF shows that aren't about the military?
Not every big government project in history has been a military one. Consider the TVA or the creation of the interstate highway system, say. Okay, those involved the Army Corps of Engineers, but it wasn't about shooting and fighting. There are times when the government is willing to invest major funding and resources in things other than warfare. That hasn't been the case much since the Reagan era, but the political pendulum's bound to swing back eventually. We'll need a major investment in science if we're to survive climate change, and developing undersea colonization or food production, sustainably of course, could be an important way to do that. So I have to disagree -- it's very plausible to me that we could see a major investment in the scientific study and development of the ocean depths over the next century. There might very well have to be.