I think I know what you are getting at, but there's an important historical dimension.

The humanities are useless, in the sense that they do not fit the current idea of what a University's place in society should be.

Universities used to teach humanities almost to all students, some years even exclusively; not because it was useful in the olden days, but precisely because it was useless. It was a luxury. A university was a place for the upper tiers of society to park their kids until they got their hormones out of their system and were mature enough to assume their new leadership role in society. By studying the humanities, students connected with the past and it elevated their spirits for the future (meaning, they could make lower class people feel stupid for not having read Goethe). Studying latin, greek, literature, ... has largely been irrelevant for centuries, but this did not matter one bit for the students (or their parents paying for it). For them, this was just a time to learn dedication to hard work, sharpen their mind, network, and hopefully not knock-up too many custodian's daughters.

Students who did not follow in their parents situation (factory owners, lawyers, physicians, what have you ...) could end up in Academia, as faculty. It kept them out of trouble, they got paid handsomely, it made for a cute dinner table story when they were rambling about their field trip to Timbuktu. The "set-for-life" (aka tenure, high pay) nature of Academia is the most important give-away that these positions had nothing to do with usefulness, and everything to do with protecting status, about ensuring excess spawn could live comfortable lives and did not embarrass their families. Academia was (is) a different kind of clergy; highly educated, a path to an unencumbered life, but also somewhat irrelevant.

The big shift is not that the humanities have become useless - they've always been. The big shift is that the university has become a vocational school. They have become, what used to be the technical and trade colleges, a replacement for the lifetime learning on the job condensed in a few years for the unwashed masses. In this neo-liberal meritocracy or ours (jk), people are widgets, and they need to be jiggered correctly so they can be slotted in to the correct spot and be useful for society. If you explained 150 years ago to Winthrop that in 2015 farmer Joe would send his kids to Harvard to learn how to operate some new fangled bleepy bloopy thingie (aka programming a computer), he'd think your nuts.

Yes, the infantile mental state of many humanities professors is baffling. I guess they dedicate themselves to their work because they are passionate about the content, yes, reading&thinking is fun! Some may even think they are useful. "I teach my students to think critically"! As if physics professor or your uncle cannot do that. "I teach my students to understand systemic societal problems!" Sure, but your adherence to those shift with the winds of political expedience, your own age and experience, and maybe that movie you once saw. But what they are really doing is that they've taken up the scraps of a role that no longer exists.

IMO, the humanities have a big place in the University - a place for "higher" learning. It elevates us over the day-to-day drab of doing errands and keeping your shoelaces tied, they connect us to some of the most wonderful human achievements of the past. But it is not useful, and has never been so.