The reason 70s are skipped now is because that demo is aged out. But generally it was skipped over because of the dominance of disco, which really was a subgenre of urban music.

The 90s get skipped over because it was dominated by dance/house music. Not only was it just music it was embrace by the "gay" community . The other dominant format was hip hop which grew from being part of the urban format into its own separate genre and format.

In the 2000s, mainstream pop and rock made a comeback at the expense of dance music.. That aud