I've got no idea where you've got the idea that any manufacturer has to supply you with an OS install disk.
Because if you buy a computer with windows pre-installed, you are purchasing an oem licence, not a hard copy of the operating system.You're paying for the OS license, so should supply you the disc. Our previous PC's have included original discs and manual, so why now the change?
As a customer, is it our right to demand a Windows install CD? A friend is interested in a laptop but I'd want to do a fresh install.