I highly doubt it will - developing cameras for professional use is fairly capital-intensive and commercial offerings have such a huge head start that the open source proposition isn't very compelling to cinematographers. The best camera is the one you have in your hands right now, not the one that sounds like it would be great in the future. Even Red camera almost choked on its own hype about the Scarlet and had to do a marketing pivot to get into the mid-price bracket.

Ultimately, people drop thousands on a pro camera in order to shoot beautiful pictures, not because they want to write their firmware, so you have a chicken-and-egg situation. And while a few people do write amazing firmware - Magic Lantern being an excellent example - that's a liability on a commercial shoot. I might use ML on an art or micro/no-budget project, but as a producer I'd probably nix the idea; you absolutely don't want to be locked into someone's quirky personal workflow to the extent that you can't fire them if they turn out to be shitty photographers or hard to work with on set.

I dunno, everything looks like vapourware until it exists. For the time being I think they're supported by EU funds and they do still seem to be making progress. I would not bet my house on it appearing though.

Of course not many people are going to literally write their own firmware, but I can see it being compelling to be able to expand your range of codecs, LUTs etc in a relatively cheap camera, and not have to put up with what the manufacturer thought you'd like.

As for ML, I think it's unlikely to destroy your shoot if you stick to the basics like the focusing and exposure tools (I forget what it actually offers tbh). RAW and more experimental features are probably a bad idea on anything serious, but then so is using a consumer Canon camera.

Agreed with everything, but bear in mind that producers are basically business managers; they're not that interested in the technical arguments but in minimizing their liability towards investors if things go bad on a project. Every producer I've ever worked with has been very conservative about innovating on workflow or depending on anything too non-standard because they don't want to be held hostage to any individual crew member, and workflow problems have killed many a project in post-production.