> That’s a bit silly of a thought experiment, because nothing survives it

I don’t think that’s true. There are developments that really do constitute genuine progress: for example, going from CRTs to LCDs. It’s hard to imagine a world populated by high-resolution, energy-efficient, colour-accurate flatscreens suddenly being replaced by the invention of a gigantic ugly box that performs worse on every available metric.

…and yet CRTs still exist as a ‘niche’ product. There’s a whole corner of the internet where people admire and collect them.

It may well be that ‘spatial computing’ or whatever you wish to call it is going to be a genuine step forward, but it’s also easy to imagine it might not be. And that’s not true for every technology.