The sentiment in general is reasonable to me: that humans are generally more effective and more productive when they have something to do and work on, even when they're not getting anywhere with their main project(s).

It's not at all clear to me that a menial job is a strong solution to that problem. I would expect that in, say, a world with UBI, that also recognized this problem, people would find better ways to keep themselves feeling like they are at least doing something and making some contribution, than working on things they don't care about or believe in. There are plenty of meaningful volunteer opportunities in the world that would be much more effective "make you feel useful" solutions than filing papers in a bureaucratic office.