That's a pity. YouTube is a treasure of awesome educational videos, better than any school can be. If only I had YouTube when I was a schoolboy... Cool people explain math (and other subjects) I could never understand but grok instantly this way. I can also hardly imagine a better media spreading cultural progress. It also promotes artistic expression, incl in poor people - have you seen the post about african teens making short scifi movies? If I had to choose just one website to give everybody on Earth access to that would be YouTube.
Nevertheless narrow content kind focus can be a problem - if somebody watches nothing but stupid/weird stuff (it may be good to have this kind of fun occasionally but one should not focus on this too much) and is suggested more and more videos of the same kind this can hardly be beneficial. Perhaps Google should invent a solution to this problem. E.g. showing some educational videos among recommendations regardless to what kind of videos you watch.