Why does all new pop music sound the same?

Actually, this thread wasn’t meant to be about all modern music, despite its somewhat inaccurate title. It was primarily aimed at the WKTU and equivalent radio stations’ playlists, which consist of exactly none of the artists mention on Kennovac’s long list and, for the most part, written by the same two guys. Obviously, there are plenty of acts around with musical value, but that is always the case. Every era has good and bad of course. You should watch the you tube videos with Jack White and Edge watching "geezer" Jimmy Page play Kasmir. They look as if they have seen god. How can this be?  

@chayro - that movie, of the three of them, was entertaining. I went with a guy who had at one point played with Link Wray. He was rolling in the aisle when "The Edge" claimed he invented the power chord. Pagey and Jack White are both OK in my book. 

@Whart - I think maybe one needs to actually be a musician to realize the contribution the rock musicians of the 60's and 70's, i.e, Page, Hendrix et al, made to the music coming later.  But again, the discussion sort of morphed from a discussion of pop music, which it was meant to be, to a discussion of all modern non-classical stuff, which it wasn't.  
But the White/Edge videos are great, as are the Leslie West videos, showing him talking about his days with Mountain and hanging out with Jimi.  Living in the past?   No - just talking about the past.  We all live in the right now.  

I am a musician. And I recognize what the musicians of 50 years ago created and contributed. Just as I recognize what Jack White has done in the past ten years has altered the musical landscape inestimably, even if I don't particularly care for his music. 

"Pop music", ironically, is a much narrower genre today than it was even 25 years ago. It's more narrowly defined; it sticks to a stricter formula. Many of The artists in Kennevacs and my previous posts aren't pop at all and have much the same dusdain for the over produced saccharine bubblegum of WKTU. 

However, there seems to be the tendency on the part of posters who consider the classic rock era as the halcyon of music to conflate all modern music into the same genre.