As long as we kept talking about the designing, implementation, and tuning of one process, we were able to keep illustrating it with vivid images (albeit in our imagination only) of pyramid building. Multiple thread management, based on the democratic principle of equality between thread pool members, had also a sense of centralized planning and supervision. Different priorities were assigned to threads programmatically, hardcoded (for most cases) after thoughtful consideration by the programmer in accordance with the expected load, and adjusted after monitoring. The upper limits of the available resources were fixed, although they could be increased after, again, a relatively big centralized decision.
Such systems had great success and still constitute the majority of the web applications currently deployed to production. Many of them are monoliths, sealed inside a single .ear or .war file. This works fine for relatively small applications and a corresponding team...