i hear you!   its unfortunately a feature of the pre-order business model that companies have to state their specs in advance in order for anyone to place an order.  And they have to appear rock solid and uber confident of their specs or people won't place an order.  If they actually said that they weren't 100% confident what the final performance would be, til the chips arrive... which is the reality... then they wouldn't get any orders, so its commercial suicide for them to be anything other than bullish about their performance specs.

its easy to say that these companies should be selling from stock... but the huge multi-millions of dollars that it takes to make a chip preclude people from doing that.  the only reason asicminer and the other early guys could afford to was simply that they were early... AND, on an old process node thats not expensive (130nm, 110nm, 65nm, 40nm.. these are cheap NREs compared to 28nm or smaller geometries).  the other guys are on newer, smaller process nodes that are much more expensive NRE (millions of dollars) to start.. and none can afford to 'fabricate' their chip without pre-orders... OR...the only other way is to raise money from... Investors.  If they have investors you can be damn sure they aren't going to sell their hardware to customers and the investors will prefer they start a private mine instead.. which is much more cost effective and profitable than selling to customers.  Thus the only way customers will get to buy miners are from the companies that haven't been funded by investors (aka, Pre-orders)

-- Jez