What if they fail? Would yelp retaliate against businesses that participated in the class action lawsuit? This possibility, even if unlikely, may dissuade many from even trying.
'If you come at the king, you best not miss.' - Omar
Class-Action lawsuits were created by lawyers who changed careers into politics and got funding for their campaign from the trial lawyers association in order to increase the amount of money trial lawyers can make
Mandatory arbitration was designed to get around class-action suits, arbitration does not create binding precedent. Constitutional originalism was invented to enshrine mandatory arbitration - if the framers of the Constitution didn't have it in mind it wasn't important or can be punted to a pernennial gridlocked legislature.
Class-action lawsuits were created to solve this exact problem?