Supmop, I disagree there. Mosaic was pretty 'risky' a decade ago.
We're in a mosaic thickening uptick. Some say it's because of the Olympics and others say its a knee-jerk industry reaction to the bad press from last year (the accusations from actresses, pulling titles, etc.).
Outside of truly indie makers like Doujin JAV studios, mosaic is definitely heavier now than just a few years ago.
A big issue I was told was how in FHD movies, there were times when watching in less than full size where it almost looked like they were uncensored.
My take is this isn't permanent and you will see studios gradually test the waters with thinner pixels.
Trust me, they hate mosaic as much as their fans. It's time-consuming to do and costs money to get right (including Ethics approval).
They aren't puritans, they're just doing what needs to be done to sell their titles.