Probably either from the fact that it got an 83 by critics, sold over 6.2 million copies in 1 year, Japan has made Lightning Farron one of the most popular female FF characters ever and the fact that the one bad official review in FF13 got critically panned by fans that Mr. Sterling and to write an "unbiased" review of the game due to being caught lying about said game:Blaze the Dragon said:I just don't get how this series is popular, I'll admit I can't speak much for the sequels, but the first game was so stupid that I just can't figure out how it was popular enough to demand sequels in the first place! It's literally a game about doing nothing.
http://www.destructoid.com/100-objective-review-final-fantasy-xiii-179178.phtml
Let's put it this way: If nobody liked the original game and the majority hated it, this would not have happened. Just saying.