I think you are missing the point. Bitcoin is the gold standard, it will survive, and no doubt the bankers will use it for their own exchanges, just as they do with gold. It's the public acceptance that is important. If the banks say - look we have got a blockchain system, and it's stable and safe, and they compare it with a Bitcoin system that is volatile, and is reported to be insecure. Which one of the two will the public choose. I believe that the biggest threat to Bitcoin isn't blocksize or stuff like that, it's exchanges that steal people money, or can't keep wallets safe.