That answer always seemed reasonable to me and I pondered it....long before I actually turned to God.
I remember as a young man I heard someone tell a story about an old Chinese man.....laying on his deathbed, asking that a missionary, some miles from where he lay, be summoned to his bedside. He had evidently always resisted this missionary's approaches to him over the years, but now, as he prepared to die he wanted to hear his message.
A runner was sent a long distance to the village where the missionary resided and upon hearing of his old adversary's plight immediately dropped everything and cranked up his old car for the trip to the man's village.
He had a flat tire......and the old man died before he could get there. He was about a half an hour late arriving. It had taken him a little over a half an hour to get the tire fixed and remounted.
This is when I made up my mind that God would see to it that somehow, someway, everyone would hear of "The Kingdom of God"......eventually.
I think it's the only answer. Any other way seems to be saying that Satan is more powerful than God.