No one is questioning whether mining with an ASIC is profitable. Hell, my SC Single can still make me $ if I had them sitting in my house even though my power is $0.35/KWH.
The thing people debate is whether paying a company to purchase a miner and then mining using your own electricity will put you ahead of flat out buying the coins. No miner currently available for pre-order seems to be able to recoup BTC opportunity cost. With BTC prices down to sub $600 now it's pretty much a no-brainer that buying mining hardware does not make sense (unless you get a deal not available to the public).
Fully agree that BTC prices are so low now that it might be more profitable to buy BTC and wait for better prices, than mining yourself. I bought my Neptunes when prices were $800 - $1100, then prices were high enough to make it an easier choice than now.
Price speculation is a 100% different game than mining. In mining you dont care too much about BTC price (as long as range stays higher than $300) because BTC price and network difficulty somehow compensate each other. Buying BTC and holding depends only on BTC price. Mining depends on several factors, then it is more insulated to BTC price. If BTC price goes over $1000, there will be so many more PetaHashes mining that you will mine less BTC than if price would be $500 per BTC.
If you buy a miner now (Neptune costs right now about 20 BTC), and prices plummet to $100, that means that the plateau phase (survival profits) will arrive much faster. Buying a Neptune when BTC prices are $100, means to pay 100 BTC for 1 Neptune. Mission impossible to mine that many BTCs. Then nobody (not even corporations) will invest 100BTC to buy a Neptune that might mine only 40-80 BTC in its lifetime. Therefore the unavoidable plateau phase. But if at that time you are mining with a Neptune that cost you 20 BTC, you will have it working for long long time still, and still mine a lot more than the 20 BTC you paid for it.
I have tried buying/selling BTC a year ago (in MtGox and then in Bitstamp), but I only lost money. Then I dont advice or comment on whether it is good or bad to buy bitcoins. Current prices of $600 looks cheap, but what if you buy and those prices go to $300 (eg. as a result of Mt Gox going bankrupt and stealing their customers funds).
Because I have got profits by mining for many months straight, then I sometimes allow myself to advice people who are thinking about mining. So far, $500 BTC prices and current mining landscape points to a still profitable 2014 (barely profitable as I tried to explain in my first post), but still allowing to recover the investment. It might be more profitable to just buy the bitcoins and wait for a year. But that is a different game than mining which was my only scope in this post.