SurlyTrader attempts to answer this question.
Right now, the IShares Investment Grade Corporate Bond ETF (LQD) earns an indicated yield of 5.05% with an average maturity of over 12 years. On the equity side, the WisdomTree Dividend ex-Financials ETF (DTN) is currently earning an indicated yield of 5.04% without the same exposure to rising interest rates. Utilities alone (XLU) have an indicated current dividend yield of 4.93%. Why would you hold long-maturity fixed income bonds in a low interest rate environment on the precipice of an inflation wave when you can earn the same income from solid equity companies with upside potential?
It basically comes down to whether the economy is entering a deflationary phase based on the de-leveraging process as a result of the collapse of the credit bubble.
Source: SurlyTrader
***