The chance that it will happen is really small and that is that many people are still dont even know how Bitcoin works so that is the problem.
If it will make it disappear than Bitcoin have to be really popular so there will be also more people that have to promote it so more people can get to know about it.
Banks will not dissapear anyway and everybody know it. Bitcoin can't compete banks, it's just need to evolve to start. When bitcoin will grow we will see what happen.
I believe banks could offer a bitcoin payment service or savings but i doubt they will support it as the countries in general are against bitcoin because it being decentralized and not regulated.