Why don't we see any more pop-up selfie cameras?

Phone manufacturers have waged a war on bezels over the last four years, and the result is that even budget phones these days have ultra-thin bezels on all sides. Thin bezels mean you get a larger screen-to-body ratio, allowing brands to cram a larger screen without increasing the dimensions of the phone. For some context, the Galaxy S9+ had a 6.2-inch panel, and the Galaxy S21 offers the same screen size even though it is 6.4mm shorter.