However "brilliant," he'd better have some fancy footwork to explain such a precise figure. I believe the old saw is true: Christ would willingly have sacrificed Himself for just a single person. And He did indeed foreknow who would believe.
That 6% figure was far more tenable statistically a century ago, when worldwide numbers of true Christians (Bible-reading, tithing, mission-supporting) were 2% or so. But the Holy Spirit is on the move! Africans and Asians are converting by tens of millions, and 20% worldwide is the current level. Some are predicting the Rapture once we reach a third.
Even after the Rapture and all believers since Peter Preached on Pentecost are gathered to the Lord Christ and taken to the Father’s House, John saw a number in Heaven who washed their ‘garment’ in the blood of the Lamb, so great a number he could not count, and yet he could count to 200,000,000 when viewing that ‘army’ moving against Israel. The Physicist might have been a pessimist at heart.
I hope you’re right. The more, the better, obviously.