The hiring test is a great filter. What you're really measuring is whether someone has taste, not whether they can use a tool.
I've noticed the same thing in code reviews. Junior devs will ship whatever Cursor spits out without reading it. Senior devs treat it like a junior's PR — useful starting point, but you still own it.
The design problem feels harder to fix though. With code you can at least run tests. With design, the feedback loop is "does this feel right" — which you can't automate away. That's probably why the quality bar is collapsing so visibly there right now.