Lovely way of visualising progress with a simple aesthetic, great job!
My main issue is the way the buildings overlap each other once you get enough of them, presumably as a side effect of being placed down randomly. If you wanted to get fancy, you could maybe have it so that if 2 buildings overlap instead of placing the new one it upgrades the old one to a skyscraper or something, giving the same amount of money over time but taking up less space.