Up went the diff on BTC to the point GPU miners could not make a profit. Now since GPU miners make up about 80%+ of the miners what did you think they were gonna do, sit by while the old guard has steak to eat, while they get bread crumbs. They are moving to the scrypt coin and nothing can be done about it. BTC are only worth something because people say they are. Well the 80%+ is getting ready to say BTC is NOT worth anything anymore. Hence LTC is rising.
Lets assume all this is true (which it isn't). LTC uses a weakened version of scrypt one which ASICs can be produced cost effectively so what happens when BTC "dies" and LTC become mainstream. The global mining revenue shoots up into the hundreds of millions of dollars a year which justifies the development of LTC ASICs?
Despite the scrypt memory requirement relaxation in LTC we are still talking about 4 or 5 orders of magnitude of higher cost. Nobody came ever close to an efficient LTC ASIC even in theoretical designs, so the point is the development of LTC ASICs is by orders of magnitude less justified than the development of BTC ASICs and therefore won't happen before LTC gains in price as much.