If Lucas and Hobson care so much about the children, they should have considered building their arts museum off the lakefront, where it never would have run into the present legal thicket and might even be under construction by now. Yet they insisted from the first on a shoreline site, as if the $743 million Lucas plans to sink into the museum entitles them to build it on prime public space. And they have apparently turned thumbs down on alternative sites west of Lake Shore Drive.