Reddit's miner expert, praeluceo, on bitcoin mining:
Many individuals are still making a profit. Namely those who made smart hardware purchases and have access to free or inexpensive power.
- If you're asking for currently commercially available hardware (I send X BTC to Joe from BitcoinTalk/112bit/etc, and in <14 days receive hardware) your answer is no, because the exchange rate of Bitcoin to USD is too depressed. Your USD is currently more valuable being converted directly into BTC without the hardware investment.
- If you're open to used miners, you may be able to purchase some already-ROI-d hardware from a miner on ebay, Craigslist, etc, who is selling their kit at or below the current ROI. This is still pretty challenging as the price continues to trend below $400, but not impossible.
- If you're looking at a pre-order, I don't care if it advertises 1 Petahash for $1,000 with delivery by January 1st, it will never, ever, ever ROI, and likely won't deliver. Never pre-order.
- If you're talking about hardware in general, including stuff that can't be purchased, then no they are not all unprofitable. Without the markup for consumers (controller on every hashing unit, fancy enclosures, inefficient cooling systems that prioritize dB over Gh, shipping, etc) the hardware can be created relatively inexpensively. Especially if you have access to a captive foundry and some decent ASIC designs.