As I posted elsewhere, I appreciate the moxie of this lawsuit against Elsevier, Wolters Kluwer, Wiley, Taylor & Francis, Springer Nature, and STM, but am not so sure this argument will go far, at least in its current form. The argument is made of three major components as described in the linked statement release.
The first part alleges that the unpaid labor of peer review is explicitly linked to an "ability to get their manuscripts published in the defendants’ preeminent journals." There is some truth here, but litigants may have trouble finding explicit wording of such a proposition by the defendants. Maybe you rely on something implicit in the culture, but then there are also 'preeminent' non-commercial journals that you might also lay the same charge.