The 50s and 60s stand out for the quality of recordings. If we define “the best era in audio” as the greatest opportunity to maximize the enjoyment of music it is now. The technology continues to advance and for those willing and able to invest in a little more than entry level gear great choices exist to suit almost any taste and any room.
What makes this era the best, however, is the unprecedented access to an endless variety of relatively well recorded music for next to nothing. A Qobuz or Tidal subscription puts the work of a seemingly endless number of artists at your fingertips. To me, there are few greater advances in the ability to enjoy critical listening than this one. When I started this journey you bought a record then maybe an 8 trac often for one or two songs you knew you liked. Unless you were fabulously wealthy ( I wasn’t) you sure weren’t going to pick up a dozen albums at the record store of unfamiliar artists just to see if they suited your taste.
The affordable access to virtually any music out there has increased my listening enjoyment more than any other advancement. I’ve discovered artists that have brought me untold hours of listening enjoyment that I would never have experienced until relatively recently, even better, the sound quality of streamed music now rivals that of physical media- not something I would have said that long ago. And the availability of products like Roon makes it even better
so, for the ability to immerse oneself in the joy of listening to music in a serious way- this is it IMHO