How do physicists decide what to study and determine the potential usefulness of their research?

Physicists don’t care about the potential usefulness of their research, that went out the window with Albert Einstein, when physicists went full tilt “theoretical”. Physicists consider themselves to be above mere practical usefulness. So, physicists try to find the most obscure things possible, then create the most sophisticated mathematical constructs possible to explain them, and, then, they will say that to understand the nature of reality you have to spend decades mastering these sophisticated mathematical constructs explaining the most obscure things possible, and, that if you don’t, you’re a “moron”. https://www.quora.com/unanswered/How-do-physicists-decide-what-to-study-and-determine-the-potential-usefulness-of-their-research