I think what happened to the larger than life porn star is they became too mainstream. Take a some underground punk/hardcore band with a somewhat small but highly dedicated fan-base. Okay, so the band pumps out a handful of releases highly praised by their fans and tour relentlessly across the US putting on high energy shows in small sweaty dives to the same fans. This band finds mainstream exceptance, gets on MTV, signs to a major label, and tours the US but only hits the biggest cities and largest arenas, but with only half the heart they put into the smaller scale shows. Guess what, most of the original fans feel cheated and turn on the band. The remaining fans(who stick by the band, but think something is not quite the same about them anymore) and the new-found fans outnumber the original fan-base, so the band is happy and laughing all the way to the bank.

How does this compare to the "Larger than Life" porn stars?

Well, porn(even in its most tamest forms) used to be considered dirty. Then people like Jenna and Asia Carrera(sp?) started showing up on Howard Stern, E!, MTV, mainstream movies, what-have-you. Suddenly porn seemed a lot more socially acceptable. People suddenly weren't ashamed of porn anymore. Well, for a lot of people, part of the thrill in porn was that it was somewhat dangerous and socially unacceptable to watch/own pornography. some people making porn thought this, too. The result, using more average girls in the movies, but doing things more extreme. This pleased these hardcore porn fans who had turned their backs on super-enhanced, drop dead gorgeous, no-way-in-hell-you-ever-have-a-chance-with type of girls and had become jaded with the by-the-numbers oral-vag-(possibly anal)-cumshot method of porn.

The larger than life pornstars' material sold very well(and likely still does), but someone felt they need to shoot something to appeal to the porn fans who felt left out when it became mainstream.

But that's just my view on things.