The analogies you have offered aren't great.

For example designers and developers both use the computer as their primary medium of working. Their outputs resemble each other very closely, despite having a different underlying form.

Contrast that to the interior designer building a house, well those are different mediums. There is no efficiency gain from the interior designer designing the plan and also implementing it. Where as with a designer working in code there is one.

Fashion designers do indeed make clothing by hand, it's a very important part of their craft. This example disproves your stance.

Fashion designers can, in general, work with fabric, yes. And an interior designer should probably have some idea of how to paint at the very least. To me with web design so much of what matters is encoded in the CSS and HTML that it is the final design product. Anything produced before is a sketch, a concept, but it's not a design.

React, Nextjs, Vue, Nuxt, and Angular are pretty much what AI is the very best at coding in my experience. Probably because they are all meant to build essentially the same thing with different curtains.