It's more that it's just like programmers who feel technical debt forces them to overhaul entire projects.

The difference is that software projects are always hot garbage that barely works. So long as end user functionality doesn't change this is at worst benign.

UI changes on the other hand are always detrimental to users who have spent the time learning how to use the software.

Just like fashion... I wonder why we don't all wear the same style as 100 years ago, no? /s

You're apparently sarcastic, but fashion really does look like nonsense to me. I'm not sure what point you're making.

That human beings, or a portion of them, like to change their external look often enough. Maybe not in every society on Earth, but surely in many of them.

This reminded me of that famous scene from The Devil Wears Prada: https://www.youtube.com/watch?v=Ja2fgquYTCg

I can understand that it is basically impossible to live separate from that sort of industry but that doesn't make it not nonsense. It's a very good scene (and a nice movie), but it doesn't change the fact that "fashion" is a moving target that exists for it's own sake. It's a signaling pathway that sprouted an enormous industry on it's back.

Which parts are nonsense?

The part where things are changed for no good reason.

I would unironically wear Taisho-era male fashion everyday if I could. Perhaps when I have my own company....

If this was true, why don't product managers just hand design tasks over to Fiverr or Upwork? Surely everyone would be happy if you only paid for design when you needed it.

Because contractor work is categorically worse than salaried work, outside of very high pay grades. Bear in mind my prejudice is entirely based on my professional experience. Perhaps a magical land exists where this is not the case, but it's not the one I live in.