While I can't fully understand a 350%+ price increase, I can understand why dry yeasts are increasing in price - quality and ease of use.
No one can argue that dry yeast quality hasn't improved dramatically since I started brewing in the early 1990s.
Ease of use is so obvious any fool can plainly see it. An 11g packet of dry yeast can be pitched into under- or non-aerated, chilled wort. Proper pitching rates will be assured assured (mid-OG ales, of course). A good ferment is pretty much idiot-proof.
Even at $6.75 per packet (Northern Brewer's price for W-34/70), it's a savings over a $6.25 Wyeast XL smack-pack and $4.99 for a pound of DME for the starter (again, ales).
Plus the ease of use - dump the packet into the cooled wort or after simple rehydration - beats building up a starter, which you must do with liquid yeasts, regardless of manufacturer, if you want to pitch properly.
Those are valuable features. The consumer should expect to pay for them.
It's analogous to cars. These days, cars are more fuel-efficient, have added safety features like airbags, and convenience features like GPS navvy systems. If you expect to pay the same for a 2010 car with all those features as you did for a 1995 car with no more features than a tape deck, the manufacturer is not gouging you; your expectations are way out of whack. Adjust them.
Cheers,
Bob