IIRC Newegg's refuses to ever settle[0], and when patent trolls find out and try to drop it[1] Newegg sues right back[2].
You do need a motivated lawyer/legal department with institutional support though.
[0] https://www.reuters.com/article/us-scotus-newegg-soverain/u-...
[1] https://arstechnica.com/tech-policy/2016/01/patent-troll-rea...
[2] https://arstechnica.com/tech-policy/2016/01/newegg-sues-pate...
The entire strategy of patent trolls is to go after targets for whom the costs of defense are disproportionately (read: prohibitively) larger than the costs of offense.
Also, there is no lawsuit here. This is a letter. The harm of ignoring a letter is simply a matter of risk management. But in short, no suit, no foul.
I have literally said this a dozen times on HN. Learn the law enough to not get bullied.
This is self-evident and documented to the point that it's absurd even to be discussing that point. Knowing the law is literally complex enough to warrant its own profession, but even so, the operational aspects of filing legal documents are prohibitively time-consuming for small businesses.