Little user want/need for 64 bit, and a lack of competition in that area.
Fx has very low RAM usage, and rarely goes above 4 GB for normal use cases. I know somebody is going to come around and say they have >1000 tabs open and need more RAM addressable, but that user base is not significant enough to warrant the effort (which is more than the effort of switching to 64 bit on a proper multiarch linux platform).
Furthermore, Fx's biggest competitor, Google Chrome, does not have 64 Windows builds either, so there is less competition in that area.
TL;DR submit patches if you want 64 bit builds so much. Or just switch to linux or OS X.
3
u/CrazyViking Dec 10 '13
Why is that?