Your post made me look at my TBR on GoodReads. A while ago I started a #1 in series shelf. It currently shows 507 books of which only 210 have been read. It seems I can't resist the possiblity of a new series but I can't find the time to follow through on it either.
Wow -- those are really amazing numbers. And (but for the numbers), that's what a large part of my just-posted "ongoing series" post looks like, too. Nothing for it but to make our way through them slowly but surely, even while starting yet more series! :)
Speechless. I'm speechless!