> the total number who are willing to walk away are far too smaller
Because people are too lazy to walk away from a bad deal or simply don't want to read the contract they're about to sign is a really poor justification.
My point there is that so few do that the market doesn't respond to capture those who do so. The justification isn't about why, it is about the money in capturing them. Making an offer for people who want to buy cell phones without arbitration, and advertising it so those people know about the option, won't cause a positive return on investment and as such doesn't happen. It is a comment on why 'just go buy from someone who doesn't do it' isn't a solution.
Look at th5dv, who doesn't have any Apple or Google accounts, or use a major U.S. mobile phone carrier. Otherwise, he has agreed to a binding arbitration clause.