I think we're about to see a shift in terms of what is a viable software product and what isn't.

In the past, if you wanted to do a task, you had to choose from one of a few (or maybe just one) incumbents and make their tool fit your task. Failing that, build your own tool, but that was expensive. If you did build your own, the tool might have value and could potentially be sold to others.

Going forward, building your own will be much easier and cheaper. Even if the incumbent tools suit the task well, you might choose to build your own for a variety of other reasons. e.g. If the incumbent raises prices or chooses to enshitify. What you will probably not do is adopt some third party's vibe-coded clone of an incumbent's tool, because that won't be customized to your needs and it won't have the track record of the incumbent. You can't trust it or control it so it will be better to build your own.

If an incumbent exists and you can now vibe-code a clone, you probably can't sell that clone "as is" and expect to be successful. You might be able to sell your services to customize and refine tools for small businesses that can't really afford to hire a solitary soul to build their own solution, but don't expect that niche to persist long-term.