content: If licensing were the sole issue, we'd all be on UFS. Windows and Linux use NTFS and ext2/3/4 almost entirely out of habit; Linux even has other filesystems that failed to take root(btrfs, for example, was originally intended to succeed ext3 before ext4 became a thing). Apple may have a reason for creating APFS other than not-invented-here syndrome, but there's nothing preventing a company with its resources to create an unencumbered, fully compatible driver for an existing one if they felt like it.