Why is the world moving to such simplistic designs?

As the world gets older, it's feels like designs are getting lazier and so basic. Fast food chains used to be flashy and unique designs, now they are just a box with plain colors. There hasn't been any "world wonders built in hundreds of years. Why is the world turning into wish a simplistic, basic, and dull world? are people's brains that zombie mode that they just accept living in a basic world?