I wonder if... I could write books

The tedium of daily life at the moment often leads me to think of new possibilities. My son brought home with him from playschool a small catalogue of children's books at discounted prices. Flicking through it, I did have to marvel at the range of books now available for children of my son's age. So many weird and wonderful looking creatures and different subjects. Some are proper books with stories, others are just pictures with captions. All of them though looked friendly and inviting, enticing the curious to look beyond the cover and get drawn into what ever wonderful world lay within.
'I could do that', I convinced myself - for all of five minutes. 'It can't be that difficult', I mused. The problem is, flicking through the catalogue, every subject seems to have been covered by a range of authors and illustrators, some familiar and some not so. What could I write about? A new odd looking monster? A boy who ends up in mysterious places? A man with a magic balloon perhaps? Nah... surely it's all been covered? It would be nice to write about a series of adventures. A boy who, at night, disappears to weird and wonderful places with his dog. Problem is, I could possibly write the first one but I'd soon run out of ideas...Nice idea but that's probably all it will ever be.