DSM, Red Star and Lalvin all sell 500 gram bricks of yeast for
$10-$25. Scale this up for beer yeast sold only in 7-11g satchets
and it would cost $50-$100 depending on brand. Even the 5g satchets of
wine yeast are sometimes less than half that of dried brewer's yeast.

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