Sure, everything you can do using RDF you could conceivably do using a different suite of technologies... but my point - if there is a broad point to make here - is that you'd wind up recreating a lot of the "stuff" that is part of the RDF ecosystem anyway, to achieve the same end.

Now maybe it's possible that someone could start from scratch and build up a system that is both much simpler does the same things... if so, fine, point me to it when it becomes available.