I think anytime the project leader announces it will cost half as much to repair you have to assume that corners are being cut.
My opinion, for what it is worth, is that they have decided the moving her is to expensive, and if the bottom of the hull is as bad as everyone thinks, moving her may be to great a risk to justify.
I believe the decision is also based on the fact she will never be recalled to active duty, and at least from what is visable is presentable and will continue to draw people and $$$.
I remember when the Massachusetts went in for her dry docking, besides replacing steel and fabricating new sea chests, they stressed that the hull below the surface would be coated in "red hand epoxy" and that it would both seal and preserve the ship better than the standard paint.
I wonder if they used that on the Missouri then painted over it.
Rusty would know more about this than me, again, only conjecture on my part.