(PS: I am not a conspiracy theorist. I acknowledge facts like the Earth is round, vaccines are safe and climate change is real. I came up with this theory because of information which works as evidence. Actual conspricy theroies work the opposite way around)
Every news article about the recent death of Jon Landu never mentions the cause of death. The closest thing to a cause of death that was ever mentioned in the media was that he had cancer for a year. It makes no sense that within the year that Jon Landu knowingly had cancer, he did not opt for kemo or some other treatment, therefore the idea that Jon Landu died from cancer is not believable. Even though Jon Landu was a very busy person, it is not reasonable that he would have not opted to try to save his life because he wanted to continue working on movie production.
Another piece of information that acts as evidence is that the Japanese whaling industry is trying to reverse its decline. Recently a new whaling ship was launched in Japan called the Kangei Maru - https://www.cnn.com/2024/05/30/asia/japan-whaling-mothership-kangei-maru-intl-hnk/index.html. The Kangei Maru is larger, faster and more technologically advanced that previous Japanese whaling ships. If the Japanese whaling industry is determined enough to build a new whaling ship even through the demand for whale meat is plummeting, it would not be surprising if they assassinated John Landu because he is a famous anti whaling person who made a blockbuster movie that had an anti whaling message. Jon Landu was probably one of the Japanese whaling industry top public enemies. It's most likely that the Japanese whaling industry paid someone to kill Landu to make it less obvious who was behind the assassination.
If it is true that the Japanese whaling industry assassinated Jon Landu, then that would actually motivate the production of more anti whaling media like Avatar TWOW. Anti whaling media should not just expose the suffering of whales but also the suffering of humans caused by the whaling industry. Maybe if this theory is true we could see a reference to Landu death in a future Avatar sequel. Whaling is a disgusting business and if it is confirmed that Jon Landu was assassinated by the Japanese whaling industry this fact will become even more clear to those who still try to justify whaling.