ASIC on scrypt would just destroy the purpose of its invention, to make it profitable for CPU users. So, if they produce in large quantity and starts selling them, scrypt would not be profitable for CPUs.
I think we can pretty much reason out now that that's impossible to sustain. If it's profitable to mine on CPUs, then more and more people with CPUs will mine. This will continue to occur, raising the difficulty, until it becomes unprofitable for most people with CPUs to mine. Then only those people whose circumstances make them especially efficient miners, such as a very low cost of electricity, will find mining profitable. This is an inescapable economic reality.
