I find it highly amusing that an individual presents a well-written but entirely speculative argument about why pop culture has supposedly stagnated in the past 20 years due to the end of the cold war, and when another individual points out that correlation does not imply causation, they immediately write an equally well-presented argument based on exactly the same correlation/causation disparity.
Was the 60s a time of unique social and cultural change that still impacts modern culture even now? Yes, absolutely. However, I think it must be noted that the time period you have selected is not a representative sample. The 60s was an exception to the rule. It was a time of unusually high change and innovation. We have returned to base levels of musical innovation, which despite being a decrease in innovation as compared to the 60s does not mean we have stagnated. A society simply cannot maintain those levels of fear, wonder, excitement, and rebellion for 50 years straight.
As for the internet destroying our culture, I think you may be missing the point. The pirates of today are driving a cultural shift. We aren't protesting in the streets or sticking flowers in guns, and as a result you might not be noticing us. But we are dismantling an industry, and rebuilding it in our own image. Market forces are changing, and we aren't playing by the rules that the music industry has tried to hold us to since the 60s--rules that have enriched not artists but executives. I don't watch TV on a television anymore...I watch it on the internet. Either a network provides it to me free of charge, slips in a few commercials, and continues to make money off my viewing their work in the format I choose...or it gets downloaded for free off the internet with slightly more hassle. If NBC, ABC, Fox, and CBS have managed to adapt to the demands of a younger generation and have found a way to place the content they provide online for us free of charge at a time of our choosing, why can't the RIAA? If they fail, it will only be because they refuse to realize that they can no longer control how we access music any more than NBC nightly news gets to dictate how I hear about what's going on in the world.
And as for this supposed stagnation, I think you might be missing a fair bit of what's going on in the world of music. In the 60s, music was just that--music. What you got at a concert and what you got on a CD were fairly similar, minus the thrill of a crowd of hysteric fans. Now, music is performance art. It combines dance and song set against a visual backdrop that greatly enhances the mood of a song and the point its trying to get across. Watch a Lady Gaga music video and you'll quickly see its as much about fashion and dance as it is about the song. Youtube the Pussycat Dolls song "Buttons" and you'll realize the song itself is one of the least impressive and artful parts of what goes into that music video: mostly its about dance, synchronization, and the beauty of the female form. And before you criticize the content too much, ask yourself just how much "I wanna hold your hand" said.