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.
All along, beginning with Adam and Eve and later with Noah, God has insisted on the production of huge numbers of humans, several tens of billions, so that even when ultimately only a minority believes (”narrow gate”) there still will be tens of billions for Him to bless in heaven. He is fully capable of closing the deal with each of them individually.