The RnS never died, its still alive and well in the NFL and college - granted teams don't call their offense the RnS anymore but everyone uses the concepts. Just like the WCO, there isn't a true WCO anymore, but there are plenty of offenses that use its concepts. The Choice and Switch routes are fairly common from HS on up, you also see the Seam and Streak reads built into a lot of modern passing concepts. It's never gone away - smart coaches take what works from other offenses and incorporate them into their own and wala here we are in the modern age of football - a melting pot of offensive styles.