Do you not follow any of their careers each of the judges have booked enough campaigns, runways, and editorials to last them a lifetime but to be a model it's more than just high fashion. All of these girls are more than a face on catwalk each one is a unique brand which is part of the point of this show to use their brand and teach these girls how to better themselves as models.
Trevofashionisto said it well.
It should be understood (and it's quite obvious) that the incentive for the judges appearing on this show is different from the contestants. Karolina, Coco and Naomi are the ones who have nothing to lose by appearing on this show. In fact, the true winner out of this show is Coco. More people will know about Coco about this show as that amazing model who can do 100 poses in 1 minute.
Naomi can throw a cell phone at her assistant, appear in court for the blood diamond scandals and do many other dramatic things and she will still be booking top notch jobs. Karolina can get criticized by the tabloids but she's still going to be a supermodel. Same with Coco. This is because they already booked Vogue covers, they already did it all.
The difference with the contestants is that with a reality show, there's a very strong possibility to shoot themselves in the foot. As Naomi would say, mark my word for it, Sandra, Christy and Brittany have already shot their careers in the foot. Everyone knows reality shows are edited to make the contestants seem like something they're not. After the show, people will remember however they were portrayed on the show and emphasize their weak points.
If I ever met Jocelyn at a casting, I would think "oh, wasn't she on The Face? wasn't she that arrogant girl?" As opposed to if Jocelyn was never on the show, I would look at her as an open canvas without any bias or presumptions about her personality. Same with Devyn as a "sore loser"..
Because you know, people in the industry do that with the girl who were on ANTM and Project Runway.. "it's that crazy religious girl from antm"...."that's the girl who fought with Jessica Alba on Project Runway." Non-top models don't get the luxury of booking work with sassy/sore loser/meek/arrogant attitudes...it's only acceptable when they're supermodel level.