100% agree with ignoring sunk costs, except with crypto being speculative by nature, I think any short term hits to USD ROI can be written off by mining and holding until price rises in the future. They just ration their sell offs to cover costs, and hold the rest in BTC to realize future gains.

We also know that there's plenty of uber-cheap electricity in places like China right now, so once new asics start flooding the markets I can't imagine them not going to use. This will probably push these miners barely getting by out at that point. Either way, it's always interesting to sit back and watch the correlations between hashrate and price, especially since Bitcoin is still so young.