Yes. Why do you think people can:
Post memes for the public to see?
Create streams dedicated to certain topics?
Interact with others on comments and memechat rooms?
Upvote and downvote memes made by other people?
Follow other users?
The difference is that those social media sites are very diversified, while Imgflip is a niche meme site. But it doesn't mean that those social media sites don't have memes. They have a lot of them. Because of this, Imgflip often fails to attract new users.
Imgflip's only saving grace from losing all of its traffic to those sites is the in-built Meme Generator. Give those sites traffic, then the problem won't be solved.