How is a former scientist going to teach your child how to read? Knowing how to read and teaching it are very different.
How is a novelist going to teach your child how to read? Even with knowledge in literature, teaching children how to read requires specific teaching methods that one does not acquire with a literature degree.
How is an engineer or mathematician going to teach your child how to add and subtract when they have not worked with children before? Knowing mathematics and teaching mathematics are two very different skill sets.
Parents, think of your own degrees. Could you go into your child's classroom and teach the subjects? Could you get the children engaged and learning in all areas? If you answered no to this question, then you are also answering no to the proposed changes Tony Bennett is proposing.