You are 100% right, we have messy incompatible systems because there is no standardization. It is arguable that standardization of something that is so subjective is always going to be problematic. Design patterns are invented all the time and they start to infect other applications/platforms and mutate over time.

The only reason the original post think that "used to be a solved problem" was because we used to have a standard for guis: win32. But obviously people wanted more powerful/flexible UIs and more importantly, cross platform guis so it eventually died off.

A lot of design innovation came because the web is extremely flexible while at the same time being extremely non-standardized.