There are currently seven billion people alive today and the Population Reference Bureau estimates that about 107 billion people have ever lived.
This means that we are nowhere near close to having more alive than dead. In fact, there are 15 dead people for every person living. We surpassed seven billion dead way back between 8000BC and AD1.
In "2001: A Space Odyssey", Arthur C Clark makes the assertion: "Behind every man now alive stand 30 ghosts, for that is the ratio by which the dead outnumber the living." But Ms Baldwin points out he was not wrong. "He was making his statement in 1968. There were maybe 3.5 billion people currently living on earth so if you use our method, that would be one living person to 29 dead."
And will we ever reach a point where there are more alive than dead? This would imply a very high rate of population growth. "Could we imagine a carrying capacity of the Earth of 100-150 billion? I find that quite unimaginable."
They're counting from 50,000 years ago, "behaviorally modern humans", instead of from 200,000 years ago, "anatomically modern humans", which seems iffy to me.