hindsight backwards, at the time how could he know ether was going to $400, what he did know is what he could steadily earn via buying the cheap hardware. he could have grabbed 30k worth of eth and lost half in a dump to $150. He took the safe path nothing wrong with that
If it crashed to 150 usd then the result would be the same, he would 3x more time to earn those 30k again because profit would crash 3x and that would be a pain for him as he would be paying for the electricity and earnings would be even smaller, the more it rises the better it is as electricity becomes trivial to pay. The end result would be the same, buying coins would still be the better choice no matter how you do.
Impressive lack of understanding of why people mine, equipment rest value, privacy, and ecosystem support.