Each lawsuit has its own reasons, of course. But here are a few common issues:

1. There aren't enough judges.

• • There simply are not enough judges in the US to handle every lawsuit filed. Many judges encourage lawyers to settle cases that can be settled to avoid clogging up the system. Sometimes they do this reflexively or without good, er, judgement and a case is settled that probably ought be fully tried.

2. It takes a long time to receive justice.

• • A typical civil case takes months to resolve. An atypical case could take years. And then be appealed for additional months or years. Many times, the plaintiff simply can't wait that long. If you're broke right now, you're not in much of a position to hold out for the big payout (and justice) you deserve.

3. Justice is expensive.

• • A personal injury lawyer would charge you at least $200 / hour to work on your behalf with an upfront retainer fee and final costs in the range of $1000 to $10000. That's for a simple case. A more complex case will cost more per hour and end up at a higher total cost. You could have them work on contingency instead, which saves you a great deal of money during the trial but your attorney may take 50% of what you are awarded. If you are paying hourly, you may very well prefer a settlement because the longer this goes on, the more you're likely to just break even. If you are paying a contingency, your lawyer may prefer a settlement because 50% of something right now is a lot better than 50% of maybe something a couple years from now. They got bills to pay, too.

4. A settlement might bring about more change.

• • In a quiet settlement, the defendant may agree to change their offending behavior in exchange for keeping the matter quiet. Assuming that they are true to their word (I'll let you decide how likely that is) this may be the best justice for the plaintiff. If the whole thing goes to a public and embarrassing trial, the defendant may be willing to go scorched earth, put the plaintiff on blast and deny any wrongdoing no matter how many confidential documents were found in their shower.

In short, there are many practical reasons why legal matters are settled rather than going to trial. It may not be the kind of justice you want to see done, but it is often the best option in an imperfect system.