Head for the hills
These mothballed part-completed planes are now effectively a pile of scrap.
There is a wonderful book called The World's Worst Aircraft by James Gilbert, in which he documents the same thing happening to, I think, the Convair 880. The problem is that once the build team has been reassigned to other work, no-one knows any longer exactly what stage of construction each plane has reached. If and when you come back to it say three months later, exactly which sections of the miles of wiring, for example, have been installed / connected up / tested? It turns it to be cheaper either to rip everything out down to the basic ariframe and start again or just to scrap it.
If I had any Boeing shares I would dump them now while there's still some residual value.