I don't think it's unusual at all...merely an indicator of how little
protection that McAfee offers. It really does miss a large number of common
vectors. I honestly cannot recall a single instance of a machine with
McAfee on it that was not compromised.
While I've not seen every machine with McCrappy on it to be infected,
I've seen just about every McCrappy machine fail to have automatic
updates.
Most times the users don't understand the interface and think they are
protected, but they didn't register the software, didn't follow the
update process, so it doesn't actually update and they are left with old
definitions. I've seen this same issue on more than 80 machines from all
different types of users.
At the same time, I've not seen a single Norton/Symantec user fail to
have working updates, or at least was aware that their subscription had
expired and they were not getting updates.