I’d say this time is slightly different in that the low real rates of the past tend to coincide with better credit conditions, but this time might find a different enabler in QE’s supposed “wealth effect”. Here’s Fed Governor Jeremy Stein first:

“For example, a prolonged period of low interest rates, of the sort we are experiencing today, can create incentives for agents to take on greater duration or credit risks, or to employ additional financial leverage, in an effort to “reach for yield.” An insurance company that has offered guaranteed minimum rates of return on some of its products might find its solvency threatened by a long stretch of low rates and feel compelled to take on added risk. A similar logic applies to a bank whose net interest margins are under pressure because low rates erode the profitability of its deposit-taking franchise.