Re: So how much...
"But think about it... Apple buys the plants, gets the money back, now has nice, shiny new plants for sale at no cost to them."
I know some people can't pass by a great deal. But it isn't such a great deal if the plants can't produce sapphire of a type and quality suitable for screens. And a reasonable production cost, which has been the issue with sapphire so far.
And Apple loaned GT $359 million. Since GT is in bankruptcy, that money is gone. If Apple bought these plants, all they would be doing, is returning money to themselves.
Also, why did GT setup so many facilities? Screens are small, and can shipped easily. Gorilla Glass was originally produced at only one factory to both keep costs down, but keep quality (and integrity of the process) high.