Harvey you're kinda forgetting the girls right before Jenna. There were a few of them that I call the last of the old school true pornstars. They were in the late 1980's when they hit the big time. Kayla Kleevage and Minka are just two of them that I know (they both live here in Vegas too) and they not only had fake boobs...but they have gigantic fake boobs.
I can also tell you from first hand experience in another field of adult entertainment: Feature Dancers. I was married to 2 different feature dancers from 1989 to 2000. They both had enormous fake jugs and it was definitely not uncommon. To be an interational feature dancer and travel the world getting top dollar, the girls had to have gigantic fake boobs.
I don't think the fake tits were part of Jenna's rise to fame. I first met her in 2000 or 2001 (I can't remember which) at Internext at the Sands Expo. And she was signing that day and had hardly any makeup on and didn't look like anything special. Just a pretty girl with no makeup which made her look kinda bland. And there was nobody waiting in line to meet her at all, at least everytime that I walked the floor and saw her. I'm not even sure people recognized her (and even when I saw her at LA Webmaster Access, as you can tell from her pictures...I wouldn't have recognized her)
I think she just has that certain "It" factor that you can't quite put your finger on.
Just like damn near everybody in the world can sing better than Mick Jagger. Yet, he has something that makes people want to hear him. It's undefinable, unteachable, and you either have it or you don't.
And when you find a girl like Jenna, who obviously has "it", and you combine that with great marketing and smart business sense...then you get a star.