I never thought Jenna Jameson was attractive at all, but she's a real trainwreck now. As for why, she's a drunk and strung out on Oxycontin. Being married to a roid-raging maniac hasn't helped her cause any, either. Her situation is bad enough that she made my 2014 dead pool roster. She recently announced that she's making "a comeback" into porn, and Wey showed us how well that's gonna go over. She'll wind up doing a stint at the Bunny Ranch to bring in a bit of cash and at some point OD, drown, or shoot herself.
As for the Pamela Anderson comparison, Pamela was a remarkably attractive young woman before she wrecked herself. Jenna didn't start from a good foundation and only got worse. Furthermore, while Pamela is also a drunk (not sure if she's a pill-popper or not), she's quite content with her place in life being a very exclusive escort. She's making insane money and enjoying herself. Jenna is miserable. Two very different stories.