You make some interesting points here. I have a masters in Chemical Engineering. While I don't really use my masters for my profession (programming), I can say that it has definitely opened a bunch of doors that would have been otherwise closed to me professionally.

Also, the rigorous curriculum that I had to follow taught me more then just chemical engineering. Having to go through the entire process of working as a TA and going through the politics of academia was difficult and it prepared me for "Real life" in a way that my dual bachelors degrees never could have.

In academics at least, people start to listen to your opinions (though maybe only slightly) and it really does change the overall dynamic of the teacher student relationship in a way that needs to be experienced to understand. Though I am a firm believer that the more you put into your education the more you will get out of it and so like you said, getting a masters is mainly about the usecase.

I also think it is really about the student as well. If you took a mediocre student and let them go to Harvard; there is no guarantee that they will find more success at such a prestigious school when compared to an average college. The same thinking can be applied to masters degrees.