The correlations between haspower and the price are very complex, but it's simply wrong to think that you can keep increasing the price by adding more hashpower - the demand for Bitcoin is the main factor, and increasing the hashpower will have very little effect on demand. This analysis would have been better if they have explored what price can be supported by existing hashpower and future hahspower, because when the price increases too fast, it's important that hashpower increase too, to maintain the game-theoretic balance that makes potential attacks unprofitable.
Everything boils down to the market dynamics and many times the market can be harsh and unforgiving -- will never care about the hashpower or whatever related to its own mining. This is the big reality we have to contend with though generally speaking we can look forward to a better Bitcoin future but of course the road to that will never be smooth and a walk-in-the-park as there will be bumps and even nails ahead.