With just Chrome and IntelliJ running on Ubuntu, I have 281 processes and kernel workers running (as reported by ps). Just stitching the apps together for display on your screen requires 3-4 different processes (and a GPU). That's why 4 logical cores is a bare minimum these days for a desktop, even if no individual application takes advantage of more than a single core.

On the server side, when we deploy a Node.js web service on AWS we start one instance per logical core, for 4-64 processes all independently serving connections.

It seems the process has become the new thread, the smallest unit you should design for. So today's workloads actually make pretty good use of all those cores. Unless you're doing high performance computing and need to squeeze every last drop of performance, processes are a straightforward way to parallelize.