It's not a paradox. Miner manufacturers have to set a price for the miner. If a miner will make 1.0 BTC over its lifetime, it is silly to sell it for less. In fact they want to sell it for as much as they think people will pay. People aren't really good at math and so they can price these things at 1.5 BTC and they sell out.
Generally I agree with you but I would think some may sell for less than it could make. The key word is it could make 1btc over its lifetime it is all just speculation. It could also make .5 or less likely 1.5. but if they sell it to us today they get what it may make over its life right away and no risk. Even better is they get you to pay for it before it even exists. So they get what a miner may make before they even make it. It is a very impressive business model.