It's worth saying that the vast majority of settlements and plea deals don't involve the super wealthy. It's just what you said, cases are expensive and time consuming, both criminal and civil cases. There's another factor though, one that just can't be overstated: they're really uncertain!

A verdict is a giant gamble, even the most solid case might run into some unforeseen event, some crazy and charismatic juror or wacky judge. It's not just the verdict itself though, damages or sentencing can vary widely, and so a lot of the time people just don't want to take chances. If a company can settle a claim without taking the risk of a trial, they usually will, because even a slam dunk case has the potential to blow up.