The difference is that when people talk about hardware, they're talking about the equivalent of film, not abstract "this is central to being a camera which works with visible-spectrum light" concepts.
> you will always have [...]
> memory, storage
First, making a distinction between memory and storage is not an "at all times, in all places" kind of thing. It's more "this is what we do now, in the past, on some systems, it was different, and it may be different in the future" kind of thing. Single-level storage is not currently popular, but it was in the past and may yet come back. It already has, in some limited contexts.
Second, we've already seen home system storage go from paper tape to magnetic tape to magnetic disk to metallic magnetic disk to solid-state NAND Flash or close equivalent. Each has vastly different performance characteristics and details in every detail.
> human interfaces
I'm sure there are some iron-clad universals in HID. I don't know which of those translate from CLIs to touch-screens to gestural interfaces to speech recognition to pupil tracking to...
> power management, booting
Two things which have changed quite a bit even in the lifetime of "vaguely IBM PC-derived" desktop computers, and even moreso if you widen your scope up and down the power curve to include handheld systems and, you know, Real Computers What Do Real Work.