Now who is the real failure
Can't write software for windows because no one is interested in getting a virus but will get a virus anyway. Strangers may use your PC for a dos attack. Your identity may get stolen. Even the biggest companies suffer big time from the bugs and lose all users waiting for a patch. Your credit card data may be public property. Microsoft never finished any OS but favour you buying a new one with new holes. The reverse compatibility does mean malicious code can run in the strangest places. Booting may take several minutes and shutting down may be impossible if the "calling home" isn't finished jet. They may patch one thing and break another over and over.
But besides that windos makes a great operating system. Much better as mac, they don't have any of this.