I don’t think this would be desirable. One of the biggest annoyances with the basic Arduino IDE is that it requires all libraries to be installed in a global directory.
This is bad, because it means you can’t just give your project to someone with a different computer, and expect it to work.
So similarly, requiring a specific
~/.platformio/platformio.ini in order to build correctly is a bad idea.
pio init could use a custom template file which is simply copied into the project directory, which would I think solve your problem