I don't think this has anything to do with design tbh. You have developers who are comfortable with HTML/CSS/JS and those who prefer to stay clear of it.
A lot of those HTML/CSS/JS folks happen to also really enjoy (and are great at) PHP/Ruby/Python etc - not so unicorn-y
Then we are reduced to two outcomes — developers become more design-aware, or designers become more dev-aware. Both are unicorn hunts, what do?