There is a growing minority of us who brew smaller batches and/or less frequently. The cost of a pitch of liquid yeast is making it harder and harder for someone like me who doesn't need 200B cells (and probably not even 100B, for that matter), and probably won't be repitching into several batches, to justify that kind of outlay. Even if a packet of dry yeast cost the same as a pack of liquid, I can easily portion that out for multiple brews.
There are a few strains that I use that are still are only available in liquid form, but I'm trying out more and more dry alternatives and moving to them whenever possible.