A house with an open window.
tim bates ~ One exploit is equally vulnerable as millions
a house has an unlocked second story window open is not equally as vulnerable as a house with all the windows busted open on the first floor, basement, and with unlocked doors on the handicap accessible entryway
in the area of security, we are not talking about one person, we are talking about thousands of viruses and worms, each seeking many different exploits - and a single exploit (which could be targeting an unlocked second story window) is not vulnerable as thousands of exploits where groups of exploits are targeting doors, basement windows, and handicap accessible entries. Those millions of other exploits are useless against the single second story unlocked window
if one weakness in home security makes it as vulnerable as dozens of weaknesses, there would be no value to locks on doors and windows
i have never seen a security person leave all the doors and windows open on their personal items, just because it is just as vulnerable, because no matter how hard the person tries, there will be at least one exploit unplugged for some period of time, and they are just as vulnerable
there is no point to virus software or firewalls if one exploit leaves a piece of equipment equally vulnerable as millions