> Is this a supply/demand issue? Is wine yeast significantly cheaper to
> propagate or something?

I think (without looking) that my dry yeast from Danstar has about
twice the yeast as my Red Star yeast packages...and it costs about 3
times as much.

Of course, you can get dozens of liquid brewing cultures for about 5-6
bucks (enough to ferment 5 gallons)...the number of wine yeast
varieties is smaller....at least from what I have seen. So maybe the
cost is in the companies maintaining the number of cultures.

What I can say for sure, is taht they use the same techniques to
propagate wine yeast as they do brewing yeast....after all it is all
saccharomyces cerevisiae. Maybe they grow the brewing yeast up on a
different culture (it is grown on molasass) than wine yeast, but I do
not see how that would be the limiting factor on cost.