We asked camera companies why their RAW formats are all different and confusing

Ultimately, RAW formats aren't that complex, and camera firmware is mostly developed in countries that don't have strong open source software traditions.

Look at the decoders for each format that darktable supports here: https://github.com/darktable-org/rawspeed/tree/develop/src/l...

It's some binary parsing, reading metadata, maybe doing some decompression-- a thousand lines of C++ on average for each format. These aren't complex codecs like HEVC and only reach JPEG complexity by embedding them as thumbnails!

Cameras absolutely could emit DNG instead, but that would require more development friction: coordination (with Adobe), potentially a language barrier, and potentially making it harder to do experimental features.

Photographers rarely care, so it doesn't appreciably impact sales. Raw processing software packages have generally good support available soon after new cameras are released.

The contents are simple. How to interpret the contents, is not simple. That is why you see internet advice advocating for keeping old raw files around, because Lightroom and Photoshop sometimes gets updates which can cram out better results from old raw files.

(Edit: I mean, if you want to get a basic debayered RGB image from a raw, that's not too hard. But if you want to cram out the most, there are a lot of devils in a lot of details. Things like estimating how many green pixels are not actually green, but light-spill from what should have been red pixels is just the beginning.)