I still think it is laziness that they haven't updated the front page.
They may have reclaimed a number of pageids by recently eliminating anything after the & in a url -- imagine how many dynamic sites use an & in the url. There were quite a few interesting hiccups generated from this with hosted galleries.
I think they also did something about the directory depth, which cuts off those people with sites that have multiple subdirectories. Based on those two things alone, they could probably reclaim a few hundred million pages.
No matter what the speculation is, only one thing matters. Are your pages still getting into google and staying there?
The 5-byte issue has been raised many many times. It is a difficult conversion to go from 4-byte to 5-byte (although you would think they would just step to 8-byte and use bignum and avoid the problem altogether) It would affect cpu performance, requiring an upgrade in cpu capacity, but, would eliminate the problem for a number of years.
However, the changes I have seen have all been algorithm based, and the fact that someone is too lazy to update the front page of the site hasn't affected or worried me.
