The average developers suck. The distribution is also unbalanced. It is bulkier on the low-skill side. Great UIs are written by above average or even exception

The average developers suck. The distribution is also unbalanced. It is bulkier on the low-skill side. Great UIs are written by above average or even exceptional developers. Such experience is tied to the real-life reasoning and combining unique years-long human experience of interacting with the world. You need true general intelligence for that.