At this point, most developers look at Roblox’s main demographic; kids, if your main goal is to make it to the front page, the best idea is to tailor your game for it. In this current period of time, low-poly / cartoon styled games appear to appeal more towards Roblox’s player base.
The reason for the domination is just the visuals of the game which appeal to children. I asked my sister about the games she plays and it seems to be quite simplistic with an end goal of satisfaction where you reach.
Games with high standards do not go mainstream, as this end goal is far too “complicated” for young children, which is why more mature children play it.
The game’s art style is subjective to player opinion, whereas the main consensus of Roblox’s player base considers a low-poly art style the basis of a successful game, which is just not the case; subjective. As a UI Designer, the implementation of UI Designing and incorporating it in a specific game style gives it more “pop” to the game itself.
Also from data, younger kids tend to use tablets or iPads, which is optimized for low-poly assets in-game. Other than looks, gameplay is essential, and it must be enjoyable for you for it to be enjoyable for other people.
In conclusion, do research before you make a game, as it tends to guide you into what kind of game to make, and what will be enjoyable for you.