Nanoclaw is the first hint I've seen of new type of software, user-customizeable code. It's not spec-to-software like in the story, but it is rather interesting. You fork it and then when you add features it self-modifies. I haven't looked deeply, but I'm not sure how you get updates after that, I guess you can probably have it pull and merge itself for a while but if you ever get to where you can't merge anymore, I'm not sure what you do.
As for spec-to-software - I am still pretty unsure about this. Right now of course we are not really that close, it takes too much iteration from a prompt to a usable piece of software, and even then you need to have a good prompt. I'm also not sure about re-generating due to variations on what the result might be. The space of acceptable solutions isn't just one program, it's lots, and if you get a random acceptable solution that might be fine for original generation, but it may be extremely annoying to randomly get a different acceptable solution when regenerating, as you need to re-learn how to use it (thinking about UI specifically here.) Maybe these are the same problem, once you can one-shot the software from a spec maybe you will not have much variation on the solution since you aren't doing a somewhat random walk there iterating on the result.
I also don't know if many users really want to generate their own solutions. That's putting a lot of work on the user to even know what a good idea is. Figuring out what the good ideas are is already a huge part of making software, probably harder than implementing it. Maybe small-(ish) businesses will, like the farmers in the story, but end-users, maybe not, at least not in general.
I do think there is SOMETHING to all this, but it's really hard to predict what it's gonna look like, which is why I appreciate this piece so much.