Hi Magnus Lewan,
Raw files are not an ISO standard. Each camera maker have different raw files for each of their cameras, and sometimes with a firmware upgrade the raw file for a camera model is changed as well; has happened. To add raw support to their software Apple along with other software producers must reverse engineer these raw coding, so yes three weeks is rather short. Software vendors such as Apple can never be ahead of the curve they are always behind it as they must await the next camera raw file. This is a never ending struggle.
Now think about five, twenty or more years in time, how will folks be able to read todays raw files. It is true software manufactures are dropping support for older raw file converters.
On a side note: To me it does not make sense saying a raw is a digital negative. Raw is a proprietary file code mated to a camera and sometimes firmware. Each camera maker has different raw coding. When I think negatives I see something I can hold and seeing it without a proprietary device. YMMV.
The above is my rant. Have a nice day.
Cordially,
RicD