I think they could have made Pam's reappearance work, if they'd done it when the original series ended. She'd only been gone for what? 4-5 years at that point? I've said before in various hypothetical threads about how would you have ended Dallas, that I would have brought that other actress back as Pam, using the explanation about her supposed fatal disease to explain her absence, say it's in remission and have her, Bobby, and Christopher leave Dallas to spend however much time she has left together away from all the drama. Sure, I agree, it may have been a bit of a reach, but not the most outlandish story for a soap opera.
I think like she says in the interview I posted, after 20 years then it's too late. So having her show up on DallasTNT and trying to realistically explain her absence that would indeed have been "desperate", as she later said.
In any case, clearly I mis-remembered what I read and heard, and was combining the two different interviews in my mind, the audio interview with Dallas Fanzine and that print interview with Ultimate Dallas. The latter is the one and only time I've seen her address the rumor of why she turned down the appearance on Conundrum, and refutes it. I've been googling a ton during my breaks here at work today, and I can't find any interview where she directly says or is quoted as saying that she would have come back if they guaranteed that it was the final episode ever. I'm not saying she never said it, just that I can't find any record of her actually saying it.
Plenty of articles online state it as a fact, including the IMDB page for the episode, but there are no citations. All we have is the fact that it was written in Barbara Cullen's book, which Victoria wrote the introduction to. But beside that, every single article I've ever seen where she talks about leaving Dallas is that when she did she never intended to return. I've even seen her compare Bobby and Pam to Romeo and Juliet, which is why she thought her exit was fitting, as the romance ended in death.
And, like I said, the more I think about it, the more absurd that supposed request sounds. I mean, if that was really Victoria’s only requirement for agreeing to appear at the time then, f**k it, why didn’t Katzman just lie to her? Tell her, yeah, sure, it’s the final episode ever. He may not have known for a fact that the series wasn’t going to be renewed for another season, but he knew there was a very strong possibility that it wouldn’t be. He was a veteran of the business, he could see the weekly ratings, he knew the show was going down, which is exactly why they came up with the ending that they did, where they at least cleared up all the current storylines, with the only opening being J.R.’s fate at the end. So tell her it’s the end, get her in the episode and there’s a greater than 50% chance that he was right. An on the off-chance that CBS did renew Dallas at the last minute? What was she gonna do? Sue them? Was she going to have a clause written into her one-episode contract that forbid any further Dallas episodes from being filmed? I’m pretty sure that couldn’t be enforced. And would that clause apply to reunion films and continuations too? Imagine TNT announcing a Dallas revival in 2011 and Victoria Principal’s lawyer in court saying “No! You can’t do that! We have a contract from 1991 saying there can never ever be another episode of Dallas!”