Even if the negotiating positions are "entirely one-sided" right now, that position leaves the door open for a competitor to capture market share by offering accounts without personal credit attachments. And yet nobody does that.
Are you sure about that?
That suggests one of two things:
No, there are other possibilities. One is that the merchants assume that you're right and everyone is going to screw them the same way. Another is that they simply don't understand the profound legal implications of a couple of lines of small print and one more signature because, like most start-ups, they're trying to build a company and not paying lawyers thousands to review dozens of pages of terms sent by every financial service provider they've contacted.