There is nothing fundamentally preventing us from securing DNS. It is not the most complicated protocol believe it or not and is extensible enough for us to secure it. Moreover a different name lookup protocol would look very similar to DNS. If you don’t quite understand what DNS does and how it works the idea of making it a government protected public service may appeal to you but that isn’t actually how it works. It’s only slightly hyperbolic to say that you want XML to be a public utility.

On the other hand things like SMTP truly are ancient. They were designed to do things that just aren’t a thing today.