Hmm, I am able to go back only 2 pages worth (25 entries per page). Apparently not the same as you, but also annoyingly limited.

Yep, I'm seeing it too. In fact they aren't even showing me 20 entries; the page seems set to load a certain amount of content instead of a certain amount of posts, so e.g. if my most recent entries are all essays by Ursula Vernon then I get, like, 5 posts, tops.