Given the nature of the lawsuit, the lawyers will probably expend hundreds of thousands of hours of labor and millions of dollars in costs before they see a dime in return, if they recover anything at all. Given the risks involved and the inability of the plaintiffs to pay for legal fees on an hourly basis and expenses as incurred, a 30% is not such a bad deal. And if the plaintiffs don't like the 30% fee, then they are free to negotiate a different fee with someone else