Granted, it's ASMR, not particularly taxing, but she's always had a good work ethic, pumping out multiple videos a week, while most do weekly at most. So once she decided to do the feet thing, it makes sense that she would really commit. You're right, that she's clearly looking into what feet people are into.
I don't expect it to last very long, though. There is an escalation of expectations with paid videos like that, especially at the insane price she's charging, that I don't think she will be willing to go to, then it'll quietly go away, I imagine.