The Gears of the Bureaucracy grind slowly.....but very thoroughly!
It takes a while for all the technical examinations and other forensics to be completed, results considered, and reports written. Just compiling the witness statements will be a time consuming process.
The 332 Crash which had both crew members survive....is still under investigation.....so you should not think this one is going to be done any quicker.
I hate to think how complicated the crash sketch and diagram will be....that alone is a huge undertaking.
The AAIB does good work.