Thinks about what this means in the big picture, Google cannot get enough people showing ads on their videos to support people who choose not to show ads. What percentage of Youtube videos don't show ads? 5% ? 10%?
Don't hate me for it, but my prediction is that the next lifeline Google will reach for will be charging money for turn by turn directions in maps. They really need to find some way other than search ads to make money.
[1] This is hyperbole, I don't think they will deindex sites but I can see it affecting the page rank.