However, mainstream rock can be used as a modernized update of classic rock if any radio station playlist has to cut back on some active rock artists and songs due to ratings and popularity demand, which is an absolute variable in each local market by each state and each franchised or locally owned radio company operation.
Meanwhile, some stations consist of playing all 40 years worth of rock hits, ranging from classic hard rock and hair metal artists all the way to 2000s hard rock and metal artists, the format is an open variable.
Acts that receive heavy airplay on classic rock stations, including The Beatles, Elton John, Fleetwood Mac, Eagles, or Supertramp receive some airplay on mainstream rock stations, albeit less frequently than acts like Green Day, Nirvana, Pearl Jam, Foo Fighters, Red Hot Chili Peppers, or Alice in Chains.
Classic hard rock artists of the mid to late 1970s to the late 1980s as well as all of the 1990s alternative and grunge artists completely highlight what mainstream rock is.
This is a following trend since almost all classic rock stations rarely play harder songs and artists within their format.