That's the problem with mining. It's filled with irrational actors. If you're looking to make a profit, you'll be competing with people (like me*) who will mine even at a loss. It might have worked for a while when hardware to hash was rare but now it's out there and cheap and you can't even hope to resell it for alternate use later.
Supply and demand dictates that this means miners end up operating at marginal profits or none at all. The only wildcard is the future price of Bitcoin. If it rises as it should, it turns into a good investment for early adopters. Of course, if everyone is expecting high prices later, that increases the loss miners are willing to mine at. Miners who are operating in this zone are likely to hold since an immediate sell means immediate loss (or they may be believers in which case they are holding simply to have later. Not everyone needs to realize short-term profits on their investments).
*I do a little mining on the side as a hobby but it's insignificant.