This is rather a very strange way of thinking. If you remove all the computers in a bank the bank will stop working too. It's all the same. Technically no money is removed in either case, unless you make a pancake out of your HDD and fry it.
Ok, so the answer is "this is never gonna happen"
Let me ask the other way around: Is this possible to happen to the banking system? I mean can a virus or something "big" eliminate every bank transaction and destory the fiat money as we know it?
All these bank accounts, all these credit cards, all these wire transfers etc. Is there a "blockchain safety" for all these everyday banking related transactions?
It sounds more possible to me. Right?
Banks are even more vulnerable. It's just that the media doesn't focus on this like it does with Bitcoin. I've read news of teens that hacked through the security of a bank, same with .govt websites.
Well, that's why Jeff Garzik started "satellite" project. Check here;
https://bitcointalksearch.org/topic/bitcoins-in-space-334701I think this satellite project is being developed in case of catastrophic failures, attacks to the network etc.
A target-spesific virus may delete/corrupt blockchain data on PC's etc... Even it's so small but it's a probability...
The main question is how is the virus going to infect 6000+ nodes and most of them are running Linux given that many host it on VPS and raspberrypi. Some people don't do anything other than making it a node. So it would be hard to get them to execute a virus.
Good luck on going through a real setup with cisco firewalls. Viruses usually infect the PC of an average Joe. People who have a very high understanding of Bitcoin (few on this forum) are usually very tech savy.