It was in wide use for jet and turbine engines, centrifuges, gyroscopes, etc, before disk drives. I don't think it will fade away.

We 'spin up' virtual machines or instances now

Because once you hit the launch button your mouse cursors starts spinning.

language is symbolic so there doesn't have to be a literal connection between the reference and referent. for example you still "boot" a computer, which comes from the concept of "bootstrapping", ie, pulling oneself up by the straps of their boots. no boots are involved.

Doubt it, though I don't think that I've used it in the context of SDD's recently since latency is that low.

I think colloquially, it's pretty much understood to mean "time between turning on and being useful"

At least one of the D's in the acronym usually means Disk, and there isn't a disk in many of these. Will that ever go, do you think?

Contrary to what others said, it will likely fall out of favor the way the floppy icon faded for "Save" functionality in GUIs. It's everywhere until one day you realize you can't find it in any of the apps you use every day.

Latest Word: it's there; paint brush: check; paint.net: check; editpad: floppy. Even Intellij Idea uses floppy. Actually from a quick glance I did not find a single application which did not use floppy icon as a save pictogram.

May be it's Mac world? Apple is eager to forget old ways.

Doing a quick survey of the apps on my machine, it seems like most have just forgone the button altogether. For those that still have the button, the floppy icon seems to still be there.

Yeah, purely from memory here but it's not that the save icon went out of fashion, but the concept of an icon bar or ribbon has gone; Microsoft's current UI standard for their native apps still has a ribbon IIRC, but I feel like that's one of the last vestiges. Using real world analogies went out the window after skeuomorphic design was no longer a thing too.

Oddly enough, for me I had trouble adjusting to the 'folder' icon (or referring to folders as folders), we grew up with the term "directory" and I never had an association with anything physical with that.