I was disappointed to see this in the first paragraph:
"In recent years, US companies have taken on record amounts of debt to fund share repurchases on an unprecedented scale in the name of enhancing shareholder value."

This is simply not the case. Dividend yields + buybacks are well within the very long term range of returns to capital, which have tended to be more than 5% for the entire history of modern US equity markets. And, corporate debt to equity levels are very low.