I don't really have a solid answer for why war and politics are more prevalent as a form of historical narrative. If you are speaking primarily about digestible history for the public (podcasts, popular histories, films, etc.), my hunch would be that people gravitate towards these narratives because the genre resonates with them. People generally have found stories of battles and armies more appealing than stories of technological advancement. Not sure if that is accurate, but it is simply an observation.

If you are speaking about historical research in general, as /u/Spoonfeedme has indicated, there is an entire field dedicated to the study of science and technology throughout history. If that is something you are interested in you might want to check out our booklist that includes a section on the topic.

I actually think that science improves almost every aspect of our lives.

This is actually a rather interesting point and one that came up recently on another thread, to which I think /u/restricteddata gave a fantastic response. The 'technological salvation' narrative -that science is the driving force of human progress and will ultimately solve our problems- is a relatively recent innovation. Our understandings of what drives the human race are not a given, and this sort of self-reflection helps us understand not only the history of science, but how ourselves and others throughout history have told the story of the human race.

There is a whole field called, unsurprisingly, the History of Science. You can start by visiting the History of Science Society, who put out Isis, an entire journal dedicated to the field.