30 years ago is different. Any porn was on VHS or older mediums that do not even exist today. Once something lands on the internet, it never goes away.
I draw the opposite conclusion--a physical medium was much likelier to be found by someone, and a lot less were made, so it was more likely to be found.
Maybe 15 years later your appearance will be different enough that no one notices, but there are stories of former porn actresses being denied jobs because of the videos floating around.
Yeah, but that's so rare. You think that will happen to all of those women?
Do you think people often watch porn that is 15 years old? Or new content?
Yes, things on the internet never go away, but that's due to the ability to search for it. For example, if you are mentioned in an article, that article will stick around, and people can "Google" you. If you use a different name, and nothing is in text form, but videos, it's pretty hard to find in the vast sea of the internet.
Unless you think face recognition technology + porn search engines will combine such that you can upload a random coworkers face 20 years from now and it will scan 20 year old porn clips and output them for you, I think it's exceedingly unlikely someone's porn career will follow them, be found by their kids, etc.
Example: The Internet (and porn on it) has been around 20+ years. If I told you "a girl in my high school was in porn on the Internet circa 1997, here is a photo and her real name, but she used a fake name at the time--everything lasts forever on the internet, I'll give you $1MM to find it" how would you even go about looking for something like that?
(This is all with the caveat that they use a fake name--if they use their real name, and it's distinct, that likely will happen).
Anyways, we're getting sidetracked on a fairly minor point overall. The current exploitation and ongoing psychological issues worry me a lot more than it being discovered for every one of them in 20 years.