This. I'm not a designer, but my wife is (we met in a design studio I was prototyping for). We were just having this conversation yesterday about how design is "appreciated" in her company, basically going through every point you listed above. It takes a huge cultural change in a company to make something better than "design by engineer" desirable. Many companies want jack of all trade generalists who can code a bit and design a bit, meaning they can be reassigned easily enough to where the work happens to be at the moment. But at the end of the day, it's all mediocre output (though sadly, it is considered acceptable).

And then anyone who plays around with photoshop or illustrator for a few days seems to think they are ready for a visual design career (and interaction design is worse!). Who needs design school? So people encounter so many bad poorly trained and experienced designers that their expectations of the profession begin to be lowered. It is frustrating for those who actually went through hard work to become skilled and experienced UXDs.

I'm personally a PL designer and see the same issues in our field (well, it is very niche, and anyone who can write a compiler wants to design a language....).