Well, first of all no one said it should be 100% secure but by far the most attacks are against systems so insecure and outdated that Windows 7 might be an upgr

Well, first of all no one said it should be 100% secure but by far the most attacks are against systems so insecure and outdated that Windows 7 might be an upgrade. It takes minutes to find US water plants or the likes running Windows XP with internet access. That's not comparable to a house. That is a used plastic bag full of cash being blown down the street. Besides you house is secure exactly because your money isn't in you house but in a bank. Your argument should be "banks aren't fortresses because...." but that is what they are and so should important software.