I don't think banks care about bitcoin as a competitive threat. The big banks don't make money with 'transaction' banking. Most of them lose money on this but do it because they have to. They make money on loans, product fees (like mortgage arrangement fees) and investment banking.

If bitcoin became a major currency they would just love to provide currency hedging and all their other products off the back of it.

But what they are truly terrified of is money laundering and sanctions. Several major banks have been fined many billions of dollars this year over not doing what they should in this area. As it stands the bitcoin world just isn't up to scratch in complying with these rules. If a bank facilitates it they are liable.

So my guess is that some banks have decided that the risk profile of any bitcoin business, especially ones that provide bitcoin to fiat exchange, are too risky to deal with.

Those that are well backed and have professional staff and controls that are proven to be good enough (maybe coinbase say) will get an exemption.

It seems harsh but honestly it's how the entire financial system deals with any money broking business. I've seen it first hand because I've consulted for companies and banks to help them comply with the rules.