It appears that, since the second year of the pandemic was the beginning of a recession, the "OTA" percentage has increased by about 2 points.
It's a bit more complicated:
When you look at demos and dayparts. This is the context of my comment above:
The live viewership for broadcasting television has been on a downward trend this century. There was a joke in an episode of "30 Rock" where Alec Baldwin's character, the struggling NBC executive Jack Donaghy, had plans to return to the glory days of Must-See TV through "science or magic."