Its called moving for a better job. Do you really think those people on the South and East side of DM, are moving out to Waukee for the schools. Most are people from rural areas that have taken a new job in the metro, and they want to live in the new parts of the metro.
The last census showed this, the population of Iowa has increased very little from outside the state, its people leaving the rural areas and moving to the cities. Only been happening for the last hundred years or so.
No one is saying these kids are getting thousands of dollars to go to a private school, but when was the last time you heard of a public school coach talking to another public school player about transferring to their school. Outside of Clear Creek and their softball program, it doesn't happen in public schools. But I have witnessed private school coaches talking to my players about transferring and have had others tell me its happening. At all of them, no clue, at Holy Trinity down here in SE Iowa. Yep.
Ahh, and the truth comes out. One school in your area may recruit and you paint all private schools with the broad brush that they must too.