Very true. Computers are not physically dangerous. But look at all the infrastructure costs eaten up by hordes of unsecured and now zombied systems. According to this Information Week article the costs of SPAM (most of which is relayed through improperly secured machines) has reached $21.58 billion USD. Now, whether you believe that figure or not, is another story all together... But, unsecured machines are also used as proxies and attack vectors for other hacking. Not to mention the identity theft opened by the information contained on those systems. So it's pretty clear that unsecured machines ARE a problem and, en masse, DO CAUSE DAMAGE (far beyond an unbalanced washing machine or some burnt leftovers).
[Well, first off, XP does not required signed drivers. (It will give a warning message on installation, but, of course, users never read those...)] If you need a truly secure system that can not be compromised by user error, signing is everything. There is no way to identify (black-list) all hostile code mutations. Exercises by AntiVirus vendors have proven that time and again. So you're stuck dealing with a white-list of allowed software, and signatures for them.
I don't disagree with your statement... All vendors could currently do more. The release cycle IS a problem. But I don't want a truly secured computer. I want a general-use computer. These two things, functionally, can never converge.
