No, you're all wrong. Wrong wrong wrong. Invincible was a fine album.
I don't think MJ's lack of promo had anything to do with a lack of faith in the material on his part. You only have to watch his fairly ropey (by MJ standards) performance at MSG or the 101-ways-to-hide-my-face YRMW video to see why he didn't promote the album more. He was clearly desperately self-conscious during this period of his career, covering his face excessively and appearing doped up to the eyeballs at times.
I think this was the main reason MJ refused to make a video for Cry and why ultimately MJ showed little interest in promoting the album.
Even just a year later, he was looking much healthier, his smile was coming back (it didn't look right in 2001) and he appeared in much better spirits. Compare any of the 2001 appearances to MJ accepting his Billboard award from 2002 live via satellite at Neverland. He looked so much better and it's only a year on from Invincible's release. I think 2001 was literally the worst possible time for Michael to release new music, as he just wasn't looking or acting healthy at the time. None of us know exactly what happened in 2001, but he'd changed drastically (both physically and in his mood) from the year before. Look at him at the Elizabeth Taylor gala at the Royal Albert Hall, only one year before Invincible:
He looked a million dollars. Fast forward one year and it was a completely different story.