We do not have the full story. Maybe 36M$ is very cheap for these 900 patents and IBM was very kind. We will probably not know before many years.
They had (and everyone has) the option to simply not file this kind of suit (or even go hog wild in the patent field). But they consistently choose to. I understand that it'd be fairly irresponsible for a large company to ignore patents, or to ignore actual, real infringement that affects its bottom line, but it is and has been blown so far out of proportion that no one in IBM's position gets a pass.
Bingo. This is a corporate organization and your needs, or really anyone's needs but the company's, are not in its best interest to consider. From the perspective of profits, playing the patent ransom game is the best decision, especially for entrenched business giants like IBM.