This is a popular opinion, but I find it difficult to believe. It relies on the notion that stockholders are fools and unable to recognize when a company destroys its long term prospects for short term gain.
The trouble is, once the short term gain is there, who are the short termers going to sell to? A bunch of suckers?
And Wall Street richly rewards companies for long term behavior - there's no other explanation for Amazon's high P/E.
Lastly, the stock market returns for the last 50 years are excellent. If the corporations were all sacrificing long term for the short term, how has such sustained growth been possible?