I got a feeling that many consumers do use desktop linux, given the recently revealed 4% desktop market share across the world. macOS has 15% market share (around 3 times desktop linux), and Windows at the dominant 72% (around 3 times macOS). See https://gs.statcounter.com/os-market-share/desktop/worldwide
I believe macOS probably is more private than Windows, but it is definitely not as private as the rest of the industry.