They do actually exist. Caltech has (had?) a group doing asynchronous microprocessors, which were most naturally expressed as channels between computation unit

They do actually exist. Caltech has (had?) a group doing asynchronous microprocessors, which were most naturally expressed as channels between computation units. (They had a subset of CSP they called CHP -- communicating hardware processes that they used for a lot of the high-level designs). As usual with nice things, the market didn't actually want it. Though Intel did buy a startup they spun out and used it mostly for switch fabric purposes.