What's the significance of fabric?
The first 'fabric' man used was animal hide and vowed plants. Using fabric allowed people to migrate to colder temperatures, fabric protecting from the elements and providing warmth. Without animal hides people might not have survived the ice age.
In more contemporary times fabric has become somewhat status symbol. Before factory-made fabric fabric had to be handwoven. That made fabric very expensive to produce. The more patterns and vivid colors you had, the more expensive the fabric. Baroque fabrics were the most extravacant (IMHO) and people dressed up to show their wealth.
Later decades the length of skirts has become a measure of the wealth of the people, as during depression the skirts went short, to save in the fabric cost.
Today, fabric used is a statement. Whether your message is 'I protect nature', 'I am against child labor' or 'I am a fashionista all tastes for fabric are catered.
You ask what is the significance of fabric? Humans are the only animals on this planet who wear clothes. Without clothes we would not be the humans we are I´d say the significance is huge.