You've described it pretty well. One of their earliest cases was in Richmond, VA and I sat in to videotape a lot of the depositions. (That's how long it's been going on -- VHS and SVHS were still in use when they started suing everyone. That was around 2000-2001.)
They admitted in depositions they were in on the meetings when the standards were drawn up and had no reason for not objecting to designs that were supposedly theirs.
I have to admit, the Rambus lawyers were polite and easy to work with. The lawyers for the other company (a German firm) were mostly from one New York office and were just plain rude and nasty.
I remember one deposition in particular where there was a top memory expert giving testimony and they asked him about flip-flops and if they were memory. They (the Rambus lawyers) were trying to get him to say a flip-flop was a one bit memory and he kept saying, "Under certain conditions." The lawyer was stumped and started getting worse and worse (the only time I saw a Rambus lawyer start to get nasty) because he not only couldn't get him to give the answer they wanted, but the lawyer had no understanding of what any Electronics 101 student would know. I had a hard time not laughing and shaking the camera during the time that topic was being covered. It was pretty clear to me that lawyer had not fully prepared and didn't know at all what the topic was with flip-flops. I would have loved to have stayed in that one all day, since I figured it would only get more technical and confuse the lawyer even more, but someone took my place so I could finish some editing.