Women in porn get boob jobs (and any cosmetic surgery really) for two main reasons as far as I can tell:
1) They think it will make them look better. By far the main reason.
2) They think they’ll be more popular with porn fans and get more work.
In terms of number 1) lots of women can be self-conscious about being flat chested and get a boob job as it gives them more self-confidence and makes them feel more feminine and sexier. It may also be that they had great natural boobs at 18 years old but gravity and/or having children has taken it’s toll and they are now self conscious that their boobs have dropped and, in their eyes, are not as aesthetically pleasing. They therefore get them done to feel better. Could also be a medical issue where they had to remove their breasts and had surgery to give them back what they’ve lost.
In terms of number 2) lots of men are attracted to women with big tits and, more importantly for porn producers, fantasise about women with big tits. There are porn fans of course (and VR fans seem particularly weighted this way) that like slender nubile teen looking girls but big boobs are still a thing. If a woman walks into a room in a low cut top with sizeable cleavage pushed up almost spilling over the top, mens eyes will be drawn to it. I am one of those people. I can enjoy petite girls like Emily Willis and Riley Ried but I also like big boobs and, sacrilegious as it may be to some, fake boobs often look better to me than real ones. They probably don’t feel better but, as I’m only a viewer, that doesn’t matter. Really standout scars don’t look great but I usually don’t notice them. Obviously there are fake boobs that don’t look great but lots do to me.
Where I’m a bit of a hypocrite is that, whilst I have no objection to fake boobs, I don’t like fake asses at all. I’m like you all are with fake boobs in that I think fake asses look a weird shape and unnatural, just entirely unattractive. There may be lots of fake asses that I don’t know are fake and look great but the ones that are clearly fake actually put me off the performer. Mia Malkova was amazing to me before the fake ass, Lana Rhoades the same, Nikki Benz the same. I went off all of them once they got their asses done.
I don’t notice the Botox/lip filler stuff as much as you guys seem to so it’s not a huge issue for me. It can go too far with the facial cosmetic surgery though where they start to get that weird cat-like face. For the most part though, it’s only fake asses that I have an issue with but I’m sure women get that done for the same reasons as fake boobs.