Maybe the demand isn't high enough to allow them to keep the price down.
Maybe they've experienced a price hike in their materials i.e. the stuff that makes the wool machine washable.
Maybe they need to cover the unforseen processing costs for their first worsted weight superwashable factory-dyed yarn.
I'm sure there are lots of reasons - Raising the profit margin is not likely to be one of them when KnitPicks ENTIRE PREMISE is bringing quality products to market at the lowest possible price to allow knitters access to a variety of fibers that were previously out of their price range - Yes there are people who can't afford wool, especially nice wools. I'm one of them.