The day-to-day job on an individual scale can definitely be pointless. In aggregate though, the point of the job ends up being to keep people employed and pay taxes. That's it!
No one will like that explanation without a perspective change, and for good reason. I'd wager most people do try to put some effort into having skills and holding down a job. It obviously sucks for that effort to go to waste.
This study is, perhaps, a sign that we should view these jobs as a form of basic income in disguise. No one's going to like that ruse because it means your skills are being wasted, sure, but the alternative is ripping the band-aid off (and it's a big one) by eliminating those jobs and moving those people to socially useful ones. This action would cause chaos, which is likely why nothing has eliminated the bullshit jobs yet.
The problem is, there likely isn't enough socially useful jobs as well paying as these pointless jobs. Even if there were, you'd need training infrastructure to transition people to new jobs.
So why then should people change their perspectives? Well, the fault of having a pointless job is not really on the person, but the economy, which has grown very quickly and added jobs without regard to how socially useful they are on a long timeline. Nothing really keeps this job growth in check except market forces, which may not be rational.
If you can mentally deal with the fact that your skills are going to waste and not being used for something socially important, and frankly stop caring as much at your job, you can use the time on the pointless job for more fulfilling things.