Long ago USC certainly was, but with only two All-American running backs in the past 37 seasons, is USC still Tailback U? Alabama's had two Heisman-Trophy winning running backs in recent years.
https://johnbaranowski.wordpress.com/2018/06/09/is-usc-still-tailback-u/
https://johnbaranowski.wordpress.com/2018/06/09/is-usc-still-tailback-u/