In summary:<p>> "To create a custom template on Wordpress you need to know PHP and you need to read through pages of complicated Wordpress documentation. For front-end designers who know HTML/CSS/Javascript, it’s completely overwhelming. They just want to design, not worry about all this technical mumbo jumbo."<p>You're either confusing <i>design</i> with FE development, or you're making excuses for laziness. In any tech profession, if you want to remain competitive then you need to keep up with the advancements. If you don't want to "worry about all this technical mumbo jumbo," then stick to design and let someone else handle the coding.
It's a bit disingenuous, I think, to consider having to know PHP in order to design templates for wordpress stifling and anti-creative, but think nothing of having to know html and css to do the same for static sites. Both represent a form of technical debt which put limitations on creative freedom. To design in a technical field but find its technical nature to be beneath contempt only suggests to me that you may be working in the wrong medium.