Hip Hop is declining as a radio format because radio can not play the majority of songs that today have lyrics that would cause FCC issues but are fine on streaming sources.
That is a separate issue.
Rock has lost most of its under-35 following. Rock formats that appeal to the older demos continue, but it's not looking good in the younger demos.
And, while there are later generation Hispanics who like rock, among the foreign-born and the first generation, there is little appeal. Yes, there are rock stations in Latin America, but vastly fewer than ever before... and they appeal predominantly to upper income listeners who don't migrate to the US. The big rock station in Buenos Aires which had over a 20 share in 2000 now gets a 4 share. In fact, the only rocker in Puerto Rico, WCAD, was sold recently because it was losing money; it is now a K-Love network station.