You can't create the take home yourself because you're drawing on your own personal domain experience.

For example I'm an expert on real time video streaming in embedded systems. It's trivial to me to program a real time system that will stream video at a lower resolution in real time from scratch. I pass that problem to your average backend web developer they're going to take 100x longer then me.

The issue is, while it may seem obvious to you that the domain is too specialized, when you yourself spend to much time in a specific domain you become biased and you start to think such knowledge is basic because you get too good at it. It's invisible to you.

Time shouldn't be the factor measured here because people have such varied backgrounds.