I'm an academic, actually an applied mathematician. I agree with much of your sentiment -- it is absolutely a privilege, to the extent of being self-indulgent, to be able to spend time thinking about the things I want to. It is in some ways a rather selfish thing to do. Can I take a job that pays more? Absolutely. Would my family benefit from that? Maybe. But I'm fortunate to be paid enough for what I do. And I do hope whatever work I do -- research, teaching, even admin -- leaves the world a little richer in some ways, regardless of whether it's "useful."
(Tangentially, whether a particular piece of knowledge is eventually found to be "useful" or not doesn't seem to have much to do with the intention or motivation of the person pursuing it. Also, I don't know there's much social status that comes from being an academic mathematician these days: other than 1 or 2 of my elderly neighbors, no one seems to think it's a big deal, least of all my students and other academics.)
(Tangentially, whether a particular piece of knowledge is eventually found to be "useful" or not doesn't seem to have much to do with the intention or motivation of the person pursuing it. Also, I don't know there's much social status that comes from being an academic mathematician these days: other than 1 or 2 of my elderly neighbors, no one seems to think it's a big deal, least of all my students and other academics.)