I know, it's impossible to say and only the creators of the game knows how much they earn. I'm curious on what amount of money we're looking at. Let's take a look at the Buildbox All Stars: https://www.buildbox.com/all-stars/ How much do you think these games are making? 4 figures, or perhaps 5 figures a day?
I think the amount of money you make will not be dependent on which game engine you use to make the game. Its all about originality of your game and LUCK, but funny enough some developers just reskin a game without any addition and they make 2-4 figures, while some just make 1. I would say from what I have seen, few of the games made with BB certainly make more than 3 figures while some are just less or = to 2 figures. So it all boils down to what marketing strategy one puts together, as BB built games will not guaranty one "Automatic find me and down me".