Led Zeppelin reached unforeseeable heights for rock genre but it was Pink Floyd that expanded this genre horizontally. They released double albums and side-long jams and broadened their width. As a Pink Floyd fan I could go on and on but this is the gist of it.
I like popularized music, but when it is overpopularized (I.e. they become too commercial just to drag in every listener thus adapting their music by compromise), the original innovative genuine underground feeling fades away forever.