The way I see it is like fashion or fashion-adjacent, at least on the consumer side. One of the big accomplishments of Jobs direction is that they made computing cool, something you'd want to display instead of a functional beige box you hide away. It's not in the background, you have these colors, elegance or attention to detail on computing you want to be seen, and new major models need to be different to keep customers engaged along with being the status symbol.

With further progression on integration/miniaturization and lower power consumption/heat output for general computing, the devices have shrunk to their bare minimum as slabs, there's very little physical to display so the fashion needed to move to software (and what online services it can be a client for). Stasis is death when you rely on selling, and maintenance is a constant cost which no one really wants to pay for.

As a side note, it's interesting to compare attitudes to the physical side to PC, where for years there was almost a pride that PC was a minimalist functional box (besides the occasional fun/weird exception), but that contrasts against now where it's hard not to get components with windows or embellished with LEDs and logos on display (and there's another weird contrast, where on one hand you have internals on display, on the other trying to minimize or hiding away the cables as though the inner workings were ugly)