wht makes the society to change it's trend?

Answer 1

The direction of the wind?
90% of people are followers. they are looking for something else to follow because what they are following is not getting them where they want to go.

Answer 2

celebrities and other figures in the public eye who can change something and set the trend instead of being laughed at as out of trend.
education, or the lack of as the case may be.
planned strategies by businesses, governments and other groups.
and lets not forget, sometimes just plain hero worship or blind following coupled with "herd mentality".