I would be interested in the long perspective of constantly reinvented gui toolkits and what he thinks is progress vs reinvention.

Early html was surely reinvention, but CSS gave us the first fine grained presentation customization mechanism.

Material design? If I was a Soviet despot... Well anyway.

Ui is alas more fashion than function. I remember the original iPhone and is realistic apps, which angered UI designers so much that we now have buttons with no visible feedback as to if they are clicked, and anonymous unicolor squares everywhere.