> Nobody is thrown in jail ever for a airplane failure analysis

...in the United States. I definitely recall watching multiple episodes of Air Disasters [1] where surviving pilots in crashes in other countries that killed passengers went to jail for things that in the US would have at most resulted in a suspended license and demotion or termination from their airline.

For example, Air France Flight 296 in 1988. Another example is Gol Transportes Aéreos Flight 1907 in 2006 in Brazil.

[1] AKA Air Emergency, Mayday, or Air Crash Investigation, depending on what country you watch in and what channel it is on.

...and the accident investigation data and reports are expressly restricted from being used in legal proceedings (Chicago Convention, Annex 13) with the intention that the process is for preventing accidents, not for prosecuting scapegoats.

If the investigations of any particular mishap were to indicate that some particular person or persons had been criminally negligent, it would be no surprise to see those people prosecuted eventually. If another team of investigators has to write a different report, they will.