Because it can't. I'm aware of only two projects that have attempted this.
1. Anthropic's C compiler. This is a buggy, unoptimized, unwieldy mess. One that can compile the Linux kernel, which is no mean feat. But it is not "fully featured." And it had an incredible array of tests to start with.
2. Cursor's web browser. This is, flatly, a trainwreck. It's built on top of massive dependencies that do incredible amounts of heavy lifting despite claims to the contrary, and never seems to have ever produced a successful build.
1. Anthropic's C compiler. This is a buggy, unoptimized, unwieldy mess. One that can compile the Linux kernel, which is no mean feat. But it is not "fully featured." And it had an incredible array of tests to start with.
2. Cursor's web browser. This is, flatly, a trainwreck. It's built on top of massive dependencies that do incredible amounts of heavy lifting despite claims to the contrary, and never seems to have ever produced a successful build.