The patent troll gets to pick and choose "soft targets" (or what they believe to be soft targets). They then get to pick and choose who they escalate against, and how. If they're good at what they do, they'll already have booked serious revenue before their first case even goes to trial.

A trial represents a huge risk for them - their patent could get invalidated, for example - so it will often make sense to settle even at a loss if an opponent will clearly put up a too risky, expensive fight compared to the potential return.