You must work for a really mediocre company?

Design makes or breaks a product. Not sure where you got the impression that it's useless and professional designers gets nothing done.

I am not contesting that UI/UX is incredibly important and hard. It’s just that 99.99% of the people in that profession are clueless.

Are 99.99% of developers clueless?

I'm just trying to understand what makes you think that in the field of design, 99.99% of the professionals are clueless? What about in the marketers? Are they also 99.99% clueless?

Trying to learn how non-designers think of the profession/professional designers.

Having worked with an excellent UX designer, specifically not a graphic designer, he was great.

The difference between him and the other ones I have run into since, he watched users use the product, he would ask users how they might operate low fi paper mock ups, before us developers even saw the design. He tried his best not to project his own preferences and idiosyncrasies on the interaction design.

On the other hand, I have not seen this since. Compared to him, in my anecdata 90% are not clueless, but pretty bad.

To add on, he was not some genius, what he did was listen.

I don't doubt that there are a number of broken companies where that is the case. Sorry if you're in such a place :/