And there is going to be no more marriages in Heaven or anything that resembles marriage. Woo-pee. So much for that great design.
We were needed to fill the Earth twice. In the beginning and after the flood. In those times, procreation was very important.
In the coming life, people didn't die anymore, at least WE didn't which means procreation is no longer needed. People are like children in the Kingdom of God and they were indeed. They all seem to lack the need for coupling and were idealists in nature just like children.
Procreation wasn't important in times of over-population as well.
When God commanded humanity to "fill the Earth" it wasn't just a matter of increasing our numbers but also to venture out. To go far beyond our place of birth. To settle far and wide and NOT congregate in one place in large numbers like we see in cities. Congestion is NOT God's plan for us but the devil's.
Crime, congestion, destitution/poverty, pollution, disease, uncleanliness, immorality are all products of people living in close proximity to each other in large numbers. It happened first in the Tower of Babel in the world's first large city and God scattered everyone far and wide to teach us the right way to live.
The Earth could only sustain a non-congested population up to the times of Ancient Egypt. Come New Testament, and the time of Christ's birth on Earth, the Earth was already over-populated then and the followers of God no longer had the urgency to get married because further congestion would only keep on worsening living conditions here on Earth as well as destroying natural habitats.
It probably isn't what the Apostles have in mind but they could certainly sense it isn't important anymore.