That's fine except the #1 reader of these codes are Point of Sales machines. Most of which can only read 2D barcodes and a specific subset of them at that. What

That's fine except the #1 reader of these codes are Point of Sales machines. Most of which can only read 2D barcodes and a specific subset of them at that. What you are describing would require almost every retail bookseller in the world who wants to sell these books to do a hardware upgrade. Not to mention distributors and everyone else along the supply chain. And libraries. And that's just the hardware. The software would need updating too as I guarantee you that most of it is written assuming ISBN format (length, checksum, character set, prefix, etc).