I don't think a satisfactory answer [or indeed any sort of answer] in fact emerged. It's a copout concept, not much more useful than "God", SFAICS.

Well, Michael, there's plenty of evidence for what happened between a few billionths of a second after the Big Bang right up to now. That evidence demolishes any concept of an eternal steady-state universe. It's not a copout because we're still looking. Copout concepts are those concepts that satisfy the incurious and the science-deniers. God is the greatest copout concept because billions of people who are told to believe in him don't question his existence, in spite of its incredibly high improbability. One concept is questioned to exhaustion, with all the scientific and intellectual resources we can muster ploughed into the quest, while the other is not allowed to be questioned at all in the minds of so many people. To equate them as both being copouts is, well, a bit of a copout really...