> Imagining what would have been required for all this to work together gives me a headache. In addition to the shared backbone interface, there would need to be software written to make an almost-endless number of configurations work smoothly for the most demanding of users.

Uh, what? It's not like there haven't been several standards for busses, I/O, and DMA inside a PC case for decades. Somehow wrapping plastic around a PCI connector makes this harder? I just don't get it. Seems like a great idea to me.