These days, movies clear $100 million at the box office pretty regularly. What used to be considered an undeniable benchmark of success is no longer that, and, in fact, oftentimes a film can gross over $100 million now and still be seen as a disappointment . However, those movies usually cost well over $100 million to make. If a movie that cost, say, $10 million achieves it, $100 million once again feels like an incredible milestone . And, if that movie does it in under a week? It’s mind-blowing. That’s the kind of success that the new film Backrooms is experiencing. After a record-setting opening weekend of about $81 million (which, coincidentally, is about how many views the original Backrooms video has on YouTube), the film has added to that total and will cross $100 million on Wednesday, less than a week into release.…