Computers.
Also what s your problem with america this, america that...for someone who despises americans you sure seem to care a lot about everything they do or dont...
The truth.
Computers killed popular music, because that upper crust of people (5-10 percent) stopped buying what the major labels gave them the second they had choice. 15 years ago the industry was led somewhat by people who really had an interest in pushing music forward and were content control for the industry.
Today all the good music is independent, and you need to spend alot of time sifting through shit to get descent stuff, but it's totally there, it's just a quality control mechanism that labels grew up on have flew.
A simple example is in sports if all the top recruiters all fled the country for china, american sports would turn to shit fast. The labels relied on audiophile to lead public opinion and they've been bipassed.