However, not all developers are really good. Sometimes you have to bring in someone to work on the design, allowing the programmer to focus on stable and performing code. That is why we have come to have designers and developers.
Similarly, not all designers are really good. Sometimes you have to bring in someone who can focus on the experience while letting the other designer focus on the style. And that is why we're starting to see multiple people take on the different design roles.
Becoming really good at your craft is hard. Some people haven't spent the time required to become really good, or don't have the interest, or in very rare cases are incapable.
Because really good people are hard to find, businesses are forced to break up the jobs up to allow multiple people to fill their niche. I don't know if it is the right thing, but I'm not sure what else can be done. We can't all hire Apple's top talent, even if money was no object.
A kickass designer + kickass developer [+ kickass writer] will create a better user experience than a self-proclaimed "UX designer/developer/guru" any day.
I mean, if you are really going to set out to hire only the best, why even look at people who are just a designer or developer? Why not hire the person who is kickass at designing, developing, and writing?
Someone who has intimate knowledge of all areas of software development is going to build a better product than three people who are only skilled in their limited subsets.
As Steve Jobs said, "Most people make the mistake of thinking design is what it looks like. That’s not what we think design is. It’s not just what it looks like and feels like. Design is how it works."
Your visual designer that can't make an interface is someone I might describe as a [graphic] artist.
Semantics, I know, but a differentiation that I (thankfully) helps to reduce the use of "UX" in job titles -- a trend I've come to dislike.