While in Saugatuck last year, I took a historical tour.
You are correct of course, but there is a little more to the story of why so much sand has come inland. Sand stayed on the beaches where it normally would because Michigan was dense forest, at least the western half from what we were told.
Early construction in Chicago had entrepreneurs ferrying back wood from Michigan to "build" Chicago. As the forest was cleared, more and more sand blew inland creating dunes and also creating the wine soil I mentioned in the other response.
Chicago Fire decimated our city. but the need for massive amounts of wood to replace structures decimated your virgin forests.
Not contradicting you Dads, just doing a "Rest of The Story" that I picked up last year that I found interesting.