What makes you think the ASICs coming to GPUs leaving BTC made the price go up?? Where do you find the causality??
noone can prove causality about anything bitcoin related for the most part. but, look at the correlation. look at the time that asics started mass coming out and the price (obviously many factors involved). the theory is that miners spent way too much on mining gear that probably wont roi in btc so them selling at a loss didn't make sense so hence driving prices up (miners refusing to sell below fiat/btc cost) - mining costs are essentially a floor at the moment. there are many theories of course. regardless, people are going against alt coins for the wrong reasons.
it's purely a "business decision" where if profit > cost or opportunity cost than you do something.
100mh (effectively 100gh in sha-2) mining is going for 10k. there's obviously higher margins there for the time being.
Price for bitcoins went up right around when they got more media publicity and the US senate hearings about bitcoins, etc. The overall movement of BTC around the bitcoin economy in a given day is far larger than the amount of coins mined in a given day, so miners have only a minimal impact on bitcoin exchange rates. It all just goes back to supply and demand.
In regards to scrypt ASICs... let's just focus on getting gen3 out into the market and make some profit off that. I'd say the next priority after that should be gen4, presumably on a 22-28nm process, which should stay profitable for a longer time, as the easy gains of process size will then be behind us and bitcoin miner ASIC process size will then only advance at the pace of technological advance, rather than doing the super quick catch up from nothing to current technology levels that we've seen over the past year.