70's, 80's OPM Music and the Manila Sound Victim of too much revival?

Familiar sound of Retro music 70', & 80's music ( revivals) seems to be playing in Metro Manila airwaves quite frequently. New artists singing the old songs, the young generation of today are surprised why their elders would know the song- and would reply simply..."its a revival". "Manila sound" may take you down to memory lane and will remind you of the voices of: VST & Co., Apo Hiking Society,Hotdog, Rey Valera, Anthony Castelo, Basil Valdez, (teen age voice)of Sharon Cuneta and the Rock & Roll Genre--Mike Hanopol, Pepe Smith and Sampaguita. Most prefer the original artists and would rather buy the original cd--- specially the die hard cd collectors who would really go out of their to a thrift specialty store the internent to find these rare recordings if the items are not sold else where---rather than the new cover version; for magnified reasons such as: the "new Artists exagerated too much", "lousy copy" etc. So. why the revivals? Only the recording experts can answer that & it better be a good reason