FX CEO John Landgraf coined the term Peak Television (aka peak TV or prestige TV) in 2015 at the annual Television Critics Association press tour in Los Angeles. At the time, it was a prophetic observation. The only problem, he also predicted the trend would soon reverse itself, something that hasn't happened yet:
"My sense is that 2015 or 2016 will represent peak TV in America and that we’ll begin to see decline coming the year after that and beyond".
Source: https://www.theatlantic.com/entertainment/archive/2015/08/have-we-reached-peak-tv/401009/ (see also the Variety write-up in August 2015)
In fact, over a hundred new shows have been added to the tally since 2015.