A case could be made that it was when there were VERY affordable heathkits, hafler kits, and dynaco kits, to introduce people to the experience of HIFI.
Of cvourse there has been great technical progress since those times, but much progress has been ignored due to the likes of spotify and lossy digital encoding.
Why invest in multi-thousand $$ system if you have a lofi source and can't hear any improvement over a boombox?