[jakevoytko]

On top of that, the software world has changed dramatically since Bazel was first released. In practice, a git hash and a compile command for a command runner are more than enough for almost everyone.

What has changed in the past ~15 years? Many libraries and plugins have their own compilers nowadays. This increases the difficulty of successfully integrating with Bazel. Even projects that feel like they should be able to properly integrate Bazel (like Kubernetes) have removed it from the project as a nuisance.

Back when it was first designed, even compiling code within the same language could be a struggle; I remember going through many iterations of DLL hell back when I was a C++ programmer. This was the "it works on my machine" era. Bazel was nice because you could just say "Download this version of this thing, and give me a BUILD file path where I can reference it." Sometimes you needed to write some Starlark, but mostly not.

But now, many projects have grown in scale and complexity and they want to have their own automated passes. Just as C++ libraries needed special library wrappers for autotools within Bazel, now you often need to write multiple library compiler/automation wrappers yourself in any context. And then you'll find that Bazel's assumptions don't match the underlying code's. For example, my work's Go codebase compiles just fine with a standard Go compiler, but gazelle pukes because (IIRC) one of our third-party codegen tools outputs files with multiple packages to the same directory. When Etsy moved its Java codebase to Bazel, they needed to do some heavy refactoring because Bazel identified dependency loops and refused to compile the project, even though it worked just fine with javac. You can always push up your monocle and derisively say "you shouldn't have multiple packages per directory! you shouldn't have dependency loops!", but you should also have a compiler that can run your code just like the underlying language without needing to influence it at all.

That's why most engineers just need command runners. All of these languages and libraries are already designed to successfully run in their own contexts. You just need something to kick off the build with repeatable arguments across machines.