The Chosen Children have always been special, and nothing makes that more obvious than the fact that only Chosen Children have the ability to know their soulmates via their digivice. Maybe the digivice counts down or maybe it shows you the name at a certain age. So as the pool of Chosen Children expands, so do the people who can more easily discover their soulmate. Obviously, Daisuke and Ken are soulmates.

*Based on a discussion we had on the Discord channel a while back