Inter partes re-exam: merely an adjunct to litigation?

The 271 blog writes: recent research strongly suggests that Inter Partes Reexamination has become "an augmentation of litigation strategy rather than an alternative" (more than half (52%) of patents in inter partes re-exams are known to be in litigation during that time).

IPBiz notes that a similar result would have been likely if "post grant review" (aka opposition) had been created via patent reform 2008. Rather than a low cost alternative to litigation, opposition would have been a higher cost supplement to re-exam (and a lower cost add-on to litigation).