Problem is that this kind of code often is brittle, full of bugs and unhandled edge cases, and evolution and maintenance is horror. But if it’s all you know you might never question it.
A game is finished at some point. You might not need to evolve the code any further. Why optimize for a use-case that rarely applies to indie-games?
Often but not always, and if they're a solo developer then maintenance might not be too bad as they might be able to keep all the logic in their head. I'm not advocating for that kind of approach, but if it lets people focus on things that the player will actually notice like the gameplay, graphics, sound, story or art then hey, what's a little shortcut?