What in the world are you talking about? What stablecoins are you talking about operating at 7tx/s? Why do stablecoins fail when there's a 'run on the bank'? You're mixing so many metaphors here that I'm not sure you know what you're talking about at all. This is a stablecoin:
https://en.wikipedia.org/wiki/Dai_(cryptocurrency). If it isn't permissionless it's not a 'stablecoin' it's an IOU.