If you of a certain age, you may remember the great American heyday of kids’ breakfast cereals. It was a glorious time — a time when supermarket aisles as long as basketball courts teemed with boxes of sugary goodness and when we were all free to buy Count Chocula cereal every day of the year.Those days are long gone. Still, since 2010, Americans have at least been able to look forward to seasonal distribution of Count Chocula cereal — and Franken-Berry, and Boo-Berry — during the September and October run-up to Halloween.Now, even this tradition is imperiled because some hipster...