Probably never. BTC is a major competition to the banks, if btc becomes a major everyday currency like fiat, then banks will go out of business. So obviously they will never support BTC or take it seriously.
I'm not so sure of that. Banks aside from everything people here despise them for, are also a business that needs to book profits every year. If it doesn't come from free will, I strongly believe that at some point they will get forced to start incorporate Bitcoin in whatever form. People constantly say how bad Bitcoin is for banks, which is true, but I don't see why banks and other financial institutions can't benefit from Bitcoin's gigantic potential and eventual level of adoption. I can even see them allowing people to buy/sell Bitcoin and other crypto through their platform. I'm not directly referring to an exchange like service such as Bitstamp, but more a dedicated service that allows you to buy and sell Bitcoin according to the latest exchange rates.