This is very true. It's earning yield versus fixed income yield that matters most. If one is out of whack with the other, then there there is arbitrage. (All things equal, if there's a much better yield in equities, then people will move money from bonds to equities, or vice versa)
The current danger is that both will move down at the same time, and then where should one invest?
The current danger is that both will move down at the same time, and then where should one invest?