Of COURSE they know that their playlists are too limited and repeat almost every 2 days and have been stagnant for 20 years.
If a programming director actually had to do research or a DJ had to do more than just jabber, why it would take more skills.
This is "good enough" for the market. < /sarcasm >
Additionally ALL mainstream chart rock has largely sucked since Woodstock (and this is someone born in 1968 talking). Every generation produces some good/great music but not every performer is worth any attention. The industry has been pushing pre-determined corporate rock for more years than they haven't. If something "good" gets on tv/radio/charts it is a fluke. The whole history of rock post Woodstock is a lie and it took 25 years for the Ramones to get their due. And they were lucky. The Saints (Australia and then UK) and The Dictators, both who preceded them will NEVER get noted in "history".
James Taylor was not rock and roll. Were Foreigner innovators? How about Bon Jovi?
Although you might not be a fan of these bands...it is just criminal that the rock and roll hall of fame has not inducted:
Rush, Van Halen, Yes,Lynyrd Skynyrd,Pat Benatar,Genesis,Kiss,Alice Cooper,Ted Nugent,Boston,Foreigner,The Moody Blues,the Doobie Brothers, The Electric Light Orchestra,Asia,Chicago and Black Sabbath.
It just boggles the mind the crap that has trumped them.