What you mean is that your real-time application was largely memory bound - other apps might require that sanely and rapidly coordinating access to shared state

What you mean is that your real-time application was largely memory bound - other apps might require that sanely and rapidly coordinating access to shared state might be more critical than the cost of memory- with a collaborative whiteboard or the backend of a MMORPG you're probably going to run into difficulties with C/C++ and Node.js might very well be useless. There are domains where shared nothing just doesn't work.