/etc contains more than just config files because it's called '/etc' and not '/config'.
Any why would you need dozens of top level directories? I can't imagine that you could name even one dozen completely orthogonal aspects of program and system configuration that can't be put into a _some_ meaningful hierarchy.
/etc contains more than just config files so /config would be a misleading (or at least overly specific) name. If we went that route we'd need dozens of top level directories to cover everything. I do prefer OSX's more user friendly directory layout but the traditional directory structure has been around for decades. It works fine.