The difficulty cannot keep going up 20-30% every 10 days. It will eventually level out because it is impossible to add that much hash power to the network that quickly once the difficulty is sky high. Exponential difficulty increases cannot continue forever.
just like the price can't keep flying up like some believe..
@ $1000 per btc, and ~3600 btc produced daily, that is a boatload of new money needed to justify the total valuation.
all the new red tape pretty much snuffed that out short term at least