If it costs $0.10 to do the task once, then you can be sure as hell it costs orders of magnitude more than $1 to vibe code a whole damn app that does that thing, especially if you want good user experience which is the whole point of custom vibe coded apps. Whereas the App Store will have an inferior, mass-market version of what you want actually priced $1.

That's not necessarily true. Vibecoding a simple JSON -> YAML converter to translate a 2MB JSON is going to be much cheaper than including that JSON in a prompt and burning hundreds of thousands of tokens. Besides, there's lots of cases where the math simply favors a bigger one-time cost rather than paying fees in perpetuity.