On top of Reidenschneider's almost-attention to detail,
I also believe Buena Vista didn't provide the goods to Criterion to make an anamorphic disc.
As far as GETTING the movie in 16x9, does anyone know if the Criterion title is officially out of print, or not? This may be a situation where Criterion still has the distribution rights to the movie, and Buena Vista can't release yet another version of the movie until those rights run out. And if that IS the case, I'm sure Buena Vista would rather wait out the rights issue and release a 16x9 Armageddon, rather than try to let Criterion release it.