Well saying that it was a mistake for MJ to lip sync the History Tour is a bold statement.
Without knowing the exact reason why he did it, one can only speculate as to the wisdom of his choice. Michael had major voice problems on the Dangerous Tour wich lead to a major abuse of pain killers. His choice for miming the History Tour could as well have been for health reasons.
As I have stated before, MJ has expressed discomfort of using his voice to much on tour. In the Moonwalk book he even talks about The Jacksons tours during the 80's and how he did not like pushing his vocal chords every concert. Laryngitis is no joke. And as Michael got older, this problem ocured more frequently.
Remember Michael toured and recorded music more frequently back then. When he did the Dangerous Tour he pushed himself to far, and payed the price. The only reason he did the History Tour was to promote the album. So based on these facts, I think it is safe to say he played it safe on that tour, hence making the RIGHT choice, not risking his health again. I knew this back then so I decided NOT to hold it against him.
Now it has been 12 years since that tour, and Michael has not strained his voice. That gives him a much bigger opportunity to do one more tour and do it live. But he is not going to take chances. He has most likely recorded vocals for some songs, and I would speculate that he intends to have those recordings as backup in case his voice should go south. That way he won't have to cancel concerts because of voice trouble.
I agree that an MJ concert with all live vocals ads to the show, but I also recognize that Michael has to take safety precautions for himself, and if he chooses to do some shows with playback, I am certainly not going to slam him for it.
Michael only needs to do ONE show live for the critics and that is the opening night.
Also, one little thing most fans seem to forget. Michael does not only sing when he sings. He screams. I know some people who play in Heavy Metal bands and who pushes their voice 110%. They never do more then one show per week, because their voice gets fucked up after every concert. Michael pushes his voice far more then most artist do when he sings live, so that ads to his problem.
If you doubt me. Scream your ass off for two hours, and try to talk the next day