Namespaces are such a useful tool, it's hard to know how to respond to that statement. Do you go through the standard library cataloging all the variable names, so that you don't duplicate them in your code? The reason you don't have to do that is because all those names are in the std:: namespace, and your code isn't, so even if you name your variables the same name as something in the standard library, you won't get an error.
As for namespaces, I've survived long enough without even knowing they existed. Call me strange, but I would have thought that to propose a radical change of standard in something that works perfectly well already, it would have to be some kind of life-altering standard - one for which the benefits would be immediately obvious.