Take note that the emo culture is not entirely unpopular anymore. There are still some people who are living the emo lifestyle although it was not as rampant as it was in the before. There was a time when it was cool so people wanted to be cool as well. Now that there are other things that are popular, only those who are truly emo are left behind.
Emo also changed and evolved by the time that new emo rock bands took the center stage back in the 2000s. If you would note the modern songs of today, there may still be some songs that seem to be inspired by the emo culture so it has not completely gone away.