When 98% of your "product" is a thin wrapper around chatGPT, you will of course end up competing against every other product that is a thin wrapper around chatGPT.
This makes more sense now that I think about it.
A legal wrapper will use domain specific legal expertise to structure and develop their product and functionality. It will likely have many functions that are specifically optimized for the legal use case.
If a wrapper can easily move across many domains, then the wrapper likely adds little value to the base model.