In the 260 weeks from 1966 to 1970, there were only thirteen musical acts responsible for every #1 album on the Billboard charts.
In the 260 weeks that accounted for the first half of the 1970s, it was 26. (hat tip to John Marks for the stat).
Sometimes, we define a golden age in a market as a time of stability, when one or a few giants capture all of our attention. AT&T telephones, Superman comics, Beatles records, IBM computers, The New York Times… and now Google. Choices are easy, the market grows without a lot of effort and we marvel over the ease of success. Ironically, the success of these winners attracts quixotic entrepreneurs, people who set out to challenge the few who are winning. While we might root for these underdogs, it turns out that they're not the ones who usually change everything. The powerful are still too powerful.
The real growth and development and the foundations for the next era are laid during the chaotic times, the times that come after the leaders have stumbled. Harry Chapin didn't trip up the Beatles, but the breakup of the Beatles allowed Harry Chapin his chance. The next golden age of journalism, of communications, of fashion, of car design–those are being established now, in a moment when it's not so crowded at the top.
The very best time to launch a new product or service is when the market appears exhausted or depleted. There's more room at the top and fewer people in a hurry to get there.