Why doesn’t the world change the architecture of the homes, and buildings to look more pretty, like in medieval times?

There are few things you need to remember about old, historic and/or period buildings and housing. You aren’t seeing the typical example from the time. You are seeing the best, most expensive, most well preserved examples. Most of the examples you’ve seen are the mega-mansions of their time.

The next thing is homes and buildings are reflections of their time. What is available to build with. What do people think is aesthetically pleasing. People like the current houses even if you think they should all be burned to the ground.

We can change any time, but cost and preference is currently driving us in different directions than medieval village.