Word around the campfire was that her super high ticket prices on the last tour weren't selling out. I paid over $900 for TWO decent seats at the Alameda County show in the gay area for my son and daughter-in-law (she loves her some Tay-Tay).
When they weren't selling out, they lowered the prices (how much, I don't know) and ADDED a second show.
Bad for me. Good for her.
$$$
That's how airline pricing works. You set a baseline price and adjust them up or down depending on demand. Ideally, you'll have tickets available right up until showtime when you'll finally sell out.
The old days of Van Halen or the Stones setting a fixed ticket price and selling out a stadium in 90 minutes are over.