If you want to see them nude, stop paying for their teases and/or somehow make them go into severe debt.
+1 to this. As long as they're making enough money to keep her and her husband happy, she's going to keep doing what she's doing. Plenty of people sign up to the site because of the tease factor and they keep signing up to catch those little glimpses that she gives from time to time. As long as those people keep paying, we won't be getting any full topless sets. It's as simple as that.
What happens to a lot of girls out there is they get greedy and think that by doing topless sets they'll get a bunch more members and make a bunch more money. Sometimes it's not greed, and it might be because the site is starting to fail. Either way that probably does work, but only for a short while. By making that step, you just lost the tease lovers. Also the people that signed up to see the goods will get their fix and then cancel. Thus the model becomes old news and ends up with less subscriptions then they started with. At that point, the model either stops doing the site or has to start shoving dildos inside themselves on camera.
Nikki is different and it's why she's lasted so long.
-She's smart and probably has the same outlook as what I mentioned above.
-She's the original NN model which gives her the strongest fan base.
-She's uniquely gorgeous enough to keep people signing up for the tease factor to keep her financially supported.
-She knows as soon as the tits come out for good, she'll be a slippery slope to retirement or on camera masturbation
She probably reads this thread and laughs hysterically at having all you guys so upset about her tits. She has the control. As long as the money keeps rolling in, she will continue to have it.