There has been a lot of accusations form banks, that bitcoin is perfect for money laundering and is used for supporting crime. I think they can do a lot of harm to bitcoin market and they will eventually start with harsh campaign against it. Do you thing it will happen and when?
War? What war are you talking about op. Banks are already using bitcoin technology called blockchain. There are some banks which are paying or accepting Bitcoins. Many are now encouraging it to. Yes there is a fear that banks may loose out business, but it's absurd nothing like this will ever happen, banks are more than happy to encourage Bitcoins as after conversion, it comes back to them.
As I see it, it's nonsense to have a war between banks and bitcoin. Banks can convert bitcoins into cash that is helpful to their daily cash flow. It's also possible to convert bitcoin into other currencies; therefore, these banks have no good reason to start a war. The truth is, the bitcoin technology which is known as "blockchain" protects their transaction round the clock.
But if people invest in Bitcoin they won't let their money laying at the banks, so the banks won't make profit from your money and pay pennies back to you. Banks work like the middleman between you and a good investment, with Bitcoin you skip this middleman and start investing by yourself, 100% profit for you, while investing with banks they pay you few percentes and enjoy all the rest of the money.
Banks hegemony ends if Bitcoin rises and get more adoption.
My point of view is when Bitcoin collapse still Banks has the real money on hold but in the other hand if Banks collapse - what would be the effect for Bitcoin? Of course you can't convert Bitcoin to any currencies and possibilities Bitcoin will have no value at all.