I think it's been proven that for a lot of them content escalation works. So they start slow and show off a little more as time goes by. If they show everything from the start, there are so many that do that they have a smaller chance of "making it".
And for a while this is how Kat was. She was getting racier in her try-ons, leaving a few slips here and there, teasing stuff.
At one point I think she decided that she can make enough money (or maybe she already has) without showing anything, so she is just milking this until it goes dry and will probably stop at that point.
I remember a time where her, Natalie Roush and Christina Khalil were kind of the same thing. None of them really showing anything. Natalie now goes topless pretty commonly, Christina lets a few slips here and there, some pussy ones as well in the lives, Kat only regressed after a point.
I honestly don't understand who still pays for her content. I don't even watch it for free anymore, let alone can imagine who would pay for it.