That's my point. None of this is news, so long as you do not exceed the output at 4 ohms, or 3 ohms, or 2 ohms, or 1 ohms. Any AVR can handle a 3 ohm dip at some output level.
Of course, it may have troubles at full rated power, depending on the frequency of the dip, and impedance testing is performed at full rated power, so ... problem averted, sort of, kind of, most of the time.
Now, amplifier manufacturers are claiming 4 ohm stable, or operationally stable down to 4 ohms with entry-level AVRs, which is one step closer towards the truth. They could claim 3 ohm stable, or operationally stable down to 3 ohms and they wouldn't necessarily be wrong!
So if someone buys a receiver now, they'll go "hey, wait a second, receiver is operationally functional down to 3 ohms, OMG, woweee! But again, it's nothing new. All depends on the volume and the frequency of the dip.