He will be there, which for a large number of his audience, is all that is required.
As I have said before, my personal belief is that pop stars should leave a body of work, and then go, legend and image intact.
There is however a massive market made up of people who don't care if their idol has aged - such things really don't matter for them, and it is they who will pay to see, and enjoy Jackson's shows.
Not for me, but that's fine, there is plenty of room in the world for all sorts of entertainment.