Sometimes, lawsuits are not filed for financial reasons. Instead, the lawsuit is merely a tool to get answers, to assign blame, or to put a company out of business by running up exorbitant legal fees. For the last strategy, the death by a thousand paper cuts, the plaintiff will refuse to settle and will push extraneous motions for years in order to build up the cost of the lawsuit.
Unethical? Quite possibly. Does it happen? All the time.
Litigation, with legitimate ends in mind or not, was one strategy formerly pursued by gun control advocates. Fortunately or not, they lost. They lost in legal decisions, and eventually, a federal law banned lawsuits against gun manufacturers.