Ha, in the case of banks, belly up might be a bold statement! But without a doubt this is very disruptive for their current business model and they have to adapt to it. My expectation is that if the banks can put something in place for SMEs soon(ish) that offers functionality in terms of transparency and fee reduction similar to Ripple - maintaining speed of execution and settlement of course - then current customers might not be inclined to change platforms simply because Ripple is a decentralised model. Now, this is assuming that the SMEs are not operating across many borders since this would change that equation. But I'm just trying to think from a customers perspective here where I believe they would be willing to pay a little bit of a premium for no hassle and perceived safety. Now, for new customers, this is obviously a whole different question but in the case of banks retention is (and should be) their top priority in my opinion.