I think we have enough anecdata that users don’t like a changing interface. They like keeping things the same, mostly.

So how can you keep generating disposable software on this layer?

And what you mostly want to change in software, is new features or handle more usage. If you do that, it needs in most cases changes to the data store and the “hand crafted core”.

So what part in practice will be disposable and how often will it be “generated again”?

Maybe for simple small stuff, like how fast Excel sheets are being made, changed and discarded? Maybe for embedded software?