1 major reason .... The nearest passport office to me is over 8 hours drive time away. In BC they only have them in Vancouver. To go down to the office would be for me to take 3 days off work. 1 travel down, 1 to stand in line and get processed, 1 to travel home. So 3 days off work plus hotel room in Vancouver for 2 nights plus gas plus meals. Not to mention the sheer cost of the passports themselves - kinda getting expensive.
Maybe everyone that lives in a passport location should have gotten it done sooner so they could take those "fastpass" people out and allocate them to the people applying for a passport that can't get to an actual passport office. The further away you are from a passport office the higher up the "to do" list you go. You live in a place with a passport office, to the bottom of the barrel you go....
BTW I got my passport in 2006 so we are good for a little while now.