I have come to the conclusion that the blogger comment counter works similarly to our Electoral College.
I have decided that each blog is allocated x-number of comment numbers. For our discussion let’s say there are only 435 comment numbers allowed. As a new post is made a comment number is taken from an older post and is used on a newer one. Similar to how our electoral college redistributes the electoral votes after a census. The actual comments never disappear, but the comment counter slowly counts down until it reaches zero.
I believe this theory on the disappearance of the blogger counter numbers holds more water than my old theory – thieving gnomes.