It's improved since the 50s because racism in hiring was legal then, until we passed a law in the 60s banning it. Social attitudes regarding race have shifted dramatically since 1990 (less than half of Americans approved of mixed race marriages then!), but it's not my impression that this has translated to less racism in hiring than 1990.
We also banned discriminating against older people in the 60s, so it's not clear where to go from here.
And that's not "all you can do". Societal attitudes regarding race have shifted dramatically over the past few decades.