I'm skeptical that disposable software of the "single use" variety will ever become a big thing simply because figuring out your requirements well enough to build a throwaway app is often more work than just doing the task manually in a text editor or spreadsheet, especially for non-programmers.

I suspect what we'll see a lot more of is software which is unapologetically written for a single person to suit their workflow.

As a personal example, I decided that setting up OpenWebUI seemed unnecessarily complicated and built my own LLM chat frontend. It has a bunch of quirks (only supports OpenRouter as a backend, uses a Dropbox app folder for syncing between my phone and desktop, absurdly inefficient representation of chat history), but it suits my needs for now and only took a weekend to build, and that's good enough.