I think the big red flag with UI/UX was that it was a new term invented for a concept we already had: HCI. Human-Computer Interaction is what it was called when

I think the big red flag with UI/UX was that it was a new term invented for a concept we already had: HCI. Human-Computer Interaction is what it was called when companies like Apple and Microsoft were releasing style guides for application developers to adhere to, to ensure their applications remained consistent with every other application on the system. By inventing a new term, that generation of designers signature that they were ignorant of that past work. And the specific choice of terminology further signalled the shift in values for the designer. It was no longer about creating optimal interface points between the human and the computer, it was about creating "an experience". It centered creating a distinct brand identity for the application through the design, a goal that is anathema to the goals of HCI. Because of this, it was not enough to use the native UI toolkit of the system, which had been carefully designed around consistent experience. It became necessary to reinvent UI tooling from scratch, with the primitive elements available in the browser engine being readily available for doing such. The cross-platform nature of the browser also presented an opportunity for the MBA- and SV-driven focus on monopoly to pursue total market dominance, rather than just creating one good app for the users you have on the one system.