I understand that modern outer layers are more functional. A leather jacket, for example, can be dressed up or down so as to be worn in a variety of situations. It is also better at keeping you warm.
However, I think capes/cloaks are more aesthetically pleasing garments. It also feels good to have the fabric flowing around you as you walk. But what do you think?
Invention of more complex and effective materials I would presume. Getting a light and thin jacket which will protect you against harshest of winters is easy these days and more to the point it’s far more practical as you can do things in it.