Because you do not have a common fig ficus carica,but a cauducous fig that needs pollination,in order to keep and ripe fruits..
The Brown Turkey Tag ,it came with mean nothing unless you bought it from someone that grow the fig ,and not some company that sale fruit trees,acquired from Wholesale companies,very cheep,of course,and turn around and sell them for a profit..

Herman - Do Figs flower? How do they get pollinated? Do they need to be pollinated by a different Fig, like apples? I have already gotten several cutting to grow from the original, but If they need a different fig to pollinate, then that wont help.

My fig is just over a year old and didnt form any fruit yet, which is expected, but I did buy it from a cheapo source, so I may be in the same boat.

Pollination,is a complex process,that need a pollination agent,(Fig wasp),and a male and Female fig.
You can research it on Google yourself.
Female,Common fig ,of Ficus carica do not need polination at all but Cauducous figs,that look exactly like Common figs are grown from seeds and sometime end up being sold as Common figs.
Those need polination,if not fruits will drop when half grown.