There have been significant changes to the U.S. patent system the past ~10 years. One of which is the ease, effectiveness, and costs of invalidating a patent.

First, spend a couple of hours analyzing the Patent Claims. Often you'll discover that you most likely do NOT infringe at all - or least highly unlikely.

Other times (albeit after having developed a bit more knowledge one-time), you'll assess with decent probability of the likeliness of being able to invalidate the patent - then the tables turn - use this as a threat against the troll. They greatly fear having their $costly patent potentially wiped out. They too are playing the odds, and even a 10-20% probability of having their patent invalidated can go a long ways to dropping the suit against you.

At the end of the day, engineers are overly afraid of patents. If they spent a little time understanding them, they could greatly reduce this exaggerated fear. It's not an insurmountable hurdle - engineers&scientists have more innate abilities then they give themselves credit for. It's more of a matter that this exaggerated fear has been drilled into them. Lawyers are incentivized to perpetuate these fears.