How would you select those smaller demographics? How would you select which small demographic's interests to push? Thought to the conclusion, practically every game is popular in a small enough sub group of users. If everything is "popular", nothing is.
A browse page is selected not by demographic, but by content. So just select a tag or two for stuff that would categorize you into the group of people that like to browse for such games.
In theory, the site could create a profile of your preferences and group you into a demographic that is shown a tailored selection. But this selection would not be called popular games. It would be called recommendations.
Anyways, putting a diversification in popular based on popularity of whatever subgroups would render the section to not be the popular section anymore. It would be the trending in special interest groups section.
Maybe the randomizer would be something you want to use. https://itch.io/randomizer