In my experience working with Designers for web and app design, they always had trouble with dynamic stuff at all levels, from program flow and elements which dynamically collapsed or expanded to using animation to illustrate things or call attention to something.

Don’t get me wrong, as a programmer I was like a toddler next to them when it came to even just awareness of the concerns related to merelly visual organisation, not counting all sorts of other concerns in a visual design some of which I’m sure I’m even not aware exist. It’s just that when it came to dynamic elements their expertise was comparativelly non-existent and they have little or no tendency to use such capabilities, even in things such as apps where they’re reasonably easy to do.

More specifically: the same kind of decision makers are behind both.