I think the bigger problem is that they are hard to write and sometimes break tooling.

I’m pretty sure they operate on tokens not AST.

proprietariable just means the code can be taken and rerelased as proprietary (no freedoms all rights reserved).

You can sell GPL licensed software. You don’t have to publish the source code publicly online.

You still own the code you release under GPL. the restriction you are describing is actually caused by the non-copyleft licences you claim to prefer. If you choose to use MIT, you are limiting which libraries you can use. If you had picked GPL to begin with, you can use any library.

Copyleft licences are the only true free software licences. All other open source licenses are just proprietariable.