[I actually know the answer to this one. One of the people behind Unicode is an Apple employee who's also a devout Mormon. He's the one responsible for adding Deseret to the Unicode standard (even though there are only one or two books ever printed in that alphabet), and is presumably the reason why Deseret is actually implemented in a font in OS X. Deseret was invented by a Mormon in the 19th century to replace our alphabet with a specifically Mormon alphabet. Kinda makes you wonder about Apple's priorities - nice to know they'll implement obscure religious alphabets virtually never used, but won't implement an alphabet actually used by a few million people. Then again, I imagine there aren't a lot of Georgian Mac users out there.]
Correction:
ranger1 pointed out that the third Jaguar CD does have an installer than contains an Armenian font. I've edited this post to reflect this fact. 