At this point, it seems like there might actually be a chance that the Avatar sequels could one day actually exist in the real world. However, making that happen won't come cheap. Yesterday production on four Avatar sequels allegedly got underway (we're still not 100% sure we believe it) all at once, marking the beginning of what could turn out to be the largest film production of all time. It will also be the most expensive as the cost is expected to exceed $1 billion when it's all said and done.
To be clear, $1 billion is almost certainly the low-end estimate for what filming four of these movies will cost. The original Avatar had an estimated budget of almost $240 million and $1 billion would see these four sequels average $250 million apiece. While there will certainly be some cost savings that comes with making all four movies together, some efforts that would have been done four times over on separate shoots may only need to be done once here, it's also been nearly a decade since the original Avatar was made and most costs have simply gone up since then. Zoe Saldana's salary demands have almost certainly increased in the last few years as she's a much bigger star now, and we don't know if she decided to give James Cameron a bulk discount.
The filming of multiple movies at once isn't an untried idea. Both the Matrix sequels and the first two Pirates of the Caribbean sequels were filmed together. Peter Jackson famously did three movies together with both The Lord of the Rings and The Hobbit. However, this will be the first time that four movies were in simultaneous production. While this is usually done, at least in part, to help get the sequels into theaters faster, that's not entirely the plan here. Avatar 2 and 3 are set to hit theaters in 2020 and 2021, however, then the movies will take a break, with the final two films arriving in 2024 and 2025.
As Deadline points out, while production is now underway, there's no estimate as to how long it will actually take and considering the last film isn't expected for nearly another decade, with a significant break in between films, it could be that the plan is to actually take regular breaks in the production over the next few years, allowing actors to work on other projects or to give the crew time to get familiar with new technologies, something we can be fairly certain James Cameron is going to want to do.
However, with production honestly and truly underway, it seems that maybe we might actually get a new Avatar film in just a little over three years. We'll believe it when we see it.