it's not a thing of egoism.
the gimp developers want to be able to make changes to their own format as they see fit.
that's complex enough, without having to worry about the effects on other software.
on the other hand, some of the gimp developers where (and i guess are) involved in the creation and development of the ORA (open raster) bitmap format.
which is an interchange format supported by a few (free) graphics programs.
this is compatible with the thoughts behind the "export" command in gimp.
the xcf contains the whole information necessary to gimp for supporting your work.
when you're ready for publishing your image, you should use the "export" command and pick one of the formats that are good for that task.
it's well known, that many people have big issues with this choice, but the more i use it, the more i think that theoretically it's a good idea...
(practically, i'm very happy that they have introduced the "file > overwrite"command.)
so what you might want are new features in ORA and a good support for them in many applications!