Not all server applications are so easy to parallelize. For example there's the database server itself, which is essentially a box that you're shoving all your data concurrency into hoping that once you start to hit its limits you will be able to rearchitect your app faster than your load is growing.
But maybe you're someone who's happy with the cores and algorithms he already has. That's OK with me. There will certainly always be problems where shared-nothing parallelism over commodity hardware is the most cost effective. But not everyone is mining Bitcoin or computing the Mandelbrot set.