Things are much more complicated than that. Ticket prices are often high shortly before a flight. That's because those tickets are usually bought by business

Things are much more complicated than that. Ticket prices are often high shortly before a flight. That's because those tickets are usually bought by business travelers who don't want to wait and are willing to pay the higher fare. So it can make sense to have 5 empty seats if you sold a few more for a premium. There's a lot of math going into optimizing ticket prices.