The plastic surgery social site, RealSelf, has reported a large increase in the number of people researching butt lift. More interesting is that the number of searches for it vary profoundly across the country. And since these numbers are in the hundreds of thousands, the data is probably quite reliable. https://nypost.com/2014/02/17/nyc-shows-highest-interest-in-brazilian-butt-lifts-in-us/
The operation would probably be more common but I think many patients havfe been scared away. Most of the before and after photos on the internet show women who ended up with buttocks much larger than anyone would ever want. It hmany of the available before and after photos and interviews with women who have had the procedure make it seem as if those who get this want disproportionately large buttocks.
But the patients I see for this procedure are generally of normal weight or even thin, whose buttock is just a bit deflated or laying flat. The procedure is more of one to refill it a bit and make it look less empty and fuller. While it is undoubtedly a bit bigger, the procedure is much more about reshaping than augmenting per se.