Apparently, Mac OS X isn't exactly a priority for them.

I think that for most purposes 32 bit had worked without much issue so it's a matter of cost vs benefit. Can you think of any issues that people face because Chrome was 32 bit? So far I'm seeing Java 8 integration, which is probably a tiny fraction of their users. Also it's not really breaking since those users can just use Firefox for that purpose. They obviously don't consider this a loss.

Security is a big one. 64-bit address spaces are inherently harder to exploit, plus, IIRC, on OS X in particular, ASLR in 32-bit processes has some weaknesses that were never fixed.

Good point! To stay on my angle, are there Chrome specific security bugs that are in the most recent builds that are exacerbated by 32bit builds?

This is true for almost any application (very few things NEED 64 bits).

Or, you know, 64 bit for a single platform isn't exactly a lifechanger they should devote their resources in.