I don't think bitcoin will be stable, because we have to look at the amount of bitcoin and the impact of the demand that will occur. I'm also not sure banks will do that, instead I think that banks will be more fortunate to implement blockchain technology and make coin fiat, and this makes more sense to my mind. Banks are approaching bitcoin at this time so as not to appear evil when implementing the technology into their systems. Bitcoin is decentral and it is detrimental because many people will play around on the value of bitcoin if banks join bitcoin.