Why does all new pop music sound the same?


Basically because it IS the same - I think anyone with ears already knows that, but there is more to it. 

https://www.youtube.com/watch?v=oVME_l4IwII
chayro
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. 
@simao - I understand what you’re saying, but, as a musician, I think you would agree that every era of music had what may be called, for lack of a better word, a "zenith". The Baroque had Bach, the Classical had Mozart and Beethoven, the romantic had, well, whomever, the Jazz era had Coltrane. However that does not invalidate all the other artists operating at the same time. It’s more popular opinion than anything else. The US cars of 1969-70, The 396 Chevelle and Camaro, the Shelby GT350-500, the Hemi Cuda, et al, are generally considered to be the considered the zenith of US car manufacture, although I would much rather drive my current vehicle than my 1970 Mustang Mach 1 from a comfort and convenience point of view. Indeed - all the car auctions show these cars have a higher value than anything else produced in the US, AFAIK. Onto music - I think it is generally accepted that the late 60s and early 70’s were the zenith of British/US rock/pop music. You are certainly free to disagree, but I think that Hendrix/Zep et al were the fountain from which it all flowed. IMO of course. This is not to say it was "better" than anything that came after, nor does it invalidate the contributions by any major artists. So, on one hand, I do consider the 60s-70’s era to be the "halcyon" as you put it, but so what? They’re gone, the 70 Mustang is gone. Now what do we do? I really don’t know. Admittedly though, it’s difficult to accept the substitute once you’ve experienced the original.
It is all the same garbage.
Autotune is the death of creativity. 
Long live Rock 'n' Roll.

There is great pop music out there. I recently went to see some live music by somebody I'd never heard of. My audio buddy is more geared to new stuff and it was his idea. Ariel Pink was the nights entertainment. It was great! I honestly couldn't believe the quality of songwriting, musicianship and show that was put on. Best night out to see live music in sometime. Gary Wilson and the Blindates opened. That is another story in its own. Less a mind opener than a blender, but also deliciously awesome stuff.