Evolution of art

"Is art unique in being able to evolve and expand over time to include things that were entirely outside or opposed to its definition?"

To me, the answer is yes. People's tastes and style has evolved from that of today's, and as the audience's opinion changes, so does the work of the artists. For the first example, let's consider music. Music is one of the oldest forms of art to exist but the type of music what parents enjoyed in the 1980s is very different from what we enjoy these days. In the 1980s, jazz and instrumental music were very popular and it was the trend those days. Nowadays, trends show that people prefer pop or rap music over jazz or instrumental. 

In recent times, there have been newer methods to "create" art. Thanks to technological developments, newer gadgets like 3D printers have come into existence. 3D printers can be used to recreate all sorts of 3 dimensional objects using a computer software and it has many artists experimenting with it. However, before 3D printers were invented, artists has no idea that such a tool could exist and that they could make art with it. This technique wasn't involved included in the definition of "art" but now is, thanks to technological advances.

For the last example, we have kaadi. Kaadi was once considered a simple man's clothes. It was cheaper and comfortable and often worn by peasants. Nowadays, people admire this fabric and consumers flock to stores to buy clothes made of this fabric. People consider it fashion and the clothes made of it as works of art designed by their respective designers. The popularisation of this fabric shows how the tables turn and how the public's opinion of art changes as time does.