If settling out of court costs $100,000 and losing a lawsuit costs $1,000,000, teaming up will be the dominant strategy as long as more than 10 firms pool resources.
Newegg claims to have spent $450,000 on the Macrosolve fight, which was about 4x the troll's initial request, but which also includes a claim against Macrosolve for legal fees. That's also more money than Macrosolve could afford to drop on a fight, basically guaranteeing them a win by outlasting the case. They've worked most of their claims down to summary dismissals or no-prejudice suit drops, so once they got the "take it to the mat" reputation established they stopped having to pay full litigation costs for most of their suits.
Review and summary judgement are definitely cheaper, but even full-litigation expenses are workable. Your accounting just has to include dropped and averted suits.
At this point, Newegg is starting to look like the brilliant player in this game. "Millions for defense, but not one cent for tribute" really is a potent philosophy, and while $100k is cheaper than fighting the case, it's not cheaper than preventing future suits before they arrive.