Personally, I haven't watched the Oscars show.....since around 1992. Yeah, it's well over twenty years....going on thirty years. I just don't care. In an entire year, I might go to three total movies and frankly....the award means very little to me in terms of getting me to watch the movie.
As for the viewer count going down? The show over the past decade (you can look over comments made by people) is mostly a political forum and folks don't care if they lose viewers or not.
So where does the lowly rated show go now?
I'm of the mind that the producers and Academy will meet in three months and discuss this whole matter and opt for some non-political type guy to moderate it. Six weeks will pass, and they will admit that they can't find such a person existing who would give them the dynamics required. So a female will be found to moderate, and the 2019 show will be another full-blast political show....which has even fewer viewers than this year's show.
All of this will lead onto a trend where the major networks finally opt around 2021....NOT to carry it, and one of the cable networks buy into this....for a much-lesser price.
The viewer count will continue to a lesser spiral, and by 2025....it'll quietly disappear as a nationally-viewed show. Maybe it'll still be data-streamed and sent live to Europe....but I think you are within ten years of seeing the Oscars amount to something of zero importance to more than seventy-percent of the American population.