Here's why:
* The Percy Jackson franchise has already had a film adaptation: "Percy Jackson & the Olympians: The Lightning Thief" was released in 2010.
* The sequel, "Sea of Monsters," was not a commercial success: It didn't live up to expectations at the box office, which may have discouraged further adaptations.
* The "Percy Jackson" series is now being adapted as a TV series: Disney+ is currently working on a TV series adaptation of the "Percy Jackson" books, starting with "The Lightning Thief." This series has been praised for its faithfulness to the source material and may focus on the original books before moving on to the "Sea of Monsters" story.
While a movie adaptation is not completely ruled out, it seems unlikely given the current circumstances. However, the success of the upcoming TV series could potentially pave the way for future "Sea of Monsters" content, either in a movie or a future season of the TV show.