what my kids spend 4-5 hours on a day, realistically

Of course with many, many interruptions, tantrums, requests (or demands) for food, fights with each other over markers, etc. And of course the day ends with a gigantic mess...tape stuck to the chairs, table and floor, markers, crayons, play-doh and pencils all over the floor and table, and a million "art projects" that heaven for bid should ever be thrown away.