What do you mean? Youtube is unquestionably one of the most successful projects ever launched? Seems like the process works astoundingly well.
Youtube survives on google's massive repertoire of products being vastly more profitable, not because it's the best of its kind.
And you honestly believe the main factor in YouTube success was the quality of the code?
That's a thought that doesn't even deserve further comment.
Did the promo process exist at YouTube's creation?
Good != Successful.
I assume that's why they wrote good and not successful.
It's an average software product with incredible scaling behind it and a lot of elbow grease to keep it chumming along, but it's not great software by the definition of "bugs actually get dealt with"
Youtube wasn't launched by Google, it was purchased.