Baby name trends are largely dictated by socioeconomic levels.
The first key idea here is that your name is not about you, but rather about your parents. Your parents are the ones responsible for choosing your name.
Thinking about this from your parents perspective, most parents desire prosperity for their children and will thus name their children after those that are more successful, causing this trickle down effect. A name will be popular among the wealthy, the middle class will desire to emulate the wealthy and name their children such, the lower class will do the same. All the while the wealthy are moving on to different names.
TV Shows and Movies can also play a role in this. There aren’t any requirements that state that the person has to be living or even real. If you look at birth records you will see a recent influx in Khalisi, Danni, and Daneris ever since Game of Thrones became popular.
There are countless examples of people exploring the name fads.
This can further be explored on Freakonomics who analyzes this topic in their pod cast.