In terms of when hifi was at its pinnacle and garnering much attention from the general public, that would have been in the latter 1950’s when hifi 33 1/3 Lps were brand new and companies aggressively marketed good sound to the masses.
Once that fad passed, things continued to move forward but fewer people payed attention to sound quality, either not caring or taking it for granted.
Which brings us to today which is the true golden age for those who care. Best sound ever available to more than ever who might care and access to any music desired on a whim via streaming. No doubt today is the golden age. The world of good sound and music as at the fingertips of more people than ever, for those who care or even think about such things anymore