The above is a copy of a chart from "Racer's Encyclopedia of Metals, Fibers & Materials" by Forbes Aird.
Perhaps I over exaggerated when I used the word "same", but notice that the Y/D values for many types of metals are fairly close - in the 500 to 700 range. An exotic metal like Titanimum approaches 1000, but clearly the cost of such a material would limit its usefulness.
Nevertheless, carbon fiber and aramid would offer much more opportunities for weight reduction.
And just for background: Aramid has been experimented with in tires for over 40 years (It used to be called Fiber B). It has some wonderful properties, but one of the down sides is that it tends to shatter like glass under compression - something steel doesn't do. Remember Polyglass tires? They disappeared for the same reason.