A lot could just be that the requirements are very different between HPC and typical message-passing business apps. In HPC, you want to squeeze every ounce of performance out of the cluster, by definition. If you could get rid of the message-passing overhead, that would be a huge speedup.

For most business processes, you don't care about performance all that much, you just want things to be easy to change. Message-passing works fairly well for that: it's easy to understand, composable, and let's you swap out one component for another as long as the interfaces are compatible.

BTW, message-passing isn't exactly untried. It's the basis for the service-oriented architectures that underlie Google, Amazon, FaceBook, and many other large businesses. It works very well for that problem domain.