The computer equivalent to "three guys with guns are standing in the middle of [a road] shooting at passing drivers" would be three gunmen gaining physical access to a datacenter - game over. We don't try to protect against that attack vector any more than civil engineers protect against terrorists when designing some intersection, except maybe we encrypt some data at rest and they put up some bollards and CCTV.
You're getting hung up on the agency aspect when the most important thing is the attack by attrition. It doesn't matter whether it is a force of nature like corrosion or all the bad actors in human civilization, the point is that it is a known quantity that will eventually degrade and break every nontrivial system.
We don't know which future zero day exploit will break our systems any more than civil engineers know which wave or car will cause the ultimate collapse, but we know that it is inevitable. That's why we have defense in depth. It is the nature of the beast.
Well if they're exists, why don't we use them for everyone on daily basis, since it'll be safer? Because they're hella expensive and resources are limited.
If any smaller shops or businesses try to implement highest security for their system, their development and operation cost can multifold easily, and the ux can be reduced due to security.
But since it isn't a regular thing I don't bother with that. My car wouldn't survive long in a real battle and I'm okay with that as I don't expect to have to drive my car in a real battle.
The warning is out to everything network connected: it is time to invest in the equivalent of armor and bullet proof glass.