I don't see how there could be any viable argument toward that equivalence. Class action lawsuits are special in that most of the plaintiffs don't have to lift a finger while a small number of plaintiffs and their lawyers prosecute the case on behalf of everyone who doesn't opt out. Mass arbitration still requires each plaintiff to individually prove their case. Companies cannot write contracts that say you can only sue us if you're one of the lucky few; each and every customer/employee must individually have some avenue of recourse or the contract is going to be ruled unconscionable because the contract is only effectively binding on one party.

When a company says "you can't come after us because we're already facing too many other similar claims", that's called bankruptcy proceedings.