You start with the cleanest most minimal config you can get away with, but over the years you keep adding small additions and tweaks until it becomes a massive behemoth that only you will ever understand the reasoning behind.
https://nigeltao.github.io/blog/2021/json-with-commas-commen...
There are a lot of implementations of all of these, such as https://github.com/tailscale/hujson
- it's weird and unfamiliar, most people prefer plain JSON
- there are too many competing standards to choose from
- most existing tools just use plain JSON (sometimes with support for non-standard features, like tsconfig allowing trailing commas, but usually poorly documented and unreliable)
Much easier just to make the leap to .ts files, which are ergonomically better in almost every way anyway.