I hope that posting a link to a good YouTube video is OK.
This was the best for me. It says how they detected that the transponder was manually switched off. As well as some things about the cabin.
Surely we are speculating. Until enough pieces, and a black box are found, anyone is. But given the slim chance to find them, I think it will be a mystery.
That the transponder was manually switched off is the first bit of information published. Way before they looked into the simulator. That came from the first committee to investigate the issue.
That the locals published “it was Shah” almost immediately was also the fact. Have you been to Malaysia? To me, they looked young, very humorous and curious. They are passionate about their politics and always have been. An interesting country. But they seem to be the people to gossip, and what I read was along, “here is what we think”, and then a lot about Shah.
Now, everyone is in his right to publish alternative versions. I think finding an aileron ruled out conspiracy versions about it being hijacked, thank god. A version about an accident would not explain switching off the transponder.
Could it be someone else inside the plane? Potentially, yes. Logically, way less likely. But if you have your own version, it will definitely bring in a new fresh insight into a story that now sounds like a constant memorial prayer.