I guess it works for some, and for some it just doesn't.
My sister tried online dating sites and she met a few, but none of them were really what she was looking for.
I know you don't want to hear that it'll happen when you least expect it, but it will!
I was not looking for a relationship 5+ years ago, I actually posted something on a site asking for help on my anxiety/social problems.
He messaged me on an instant messanger and we became good friends fast, and in the same month we became a couple. He lived in a completely different state and it was difficult, but now we are together. He's my first and last real life boyfriend...go figure.
So, they can work, but it'll probably happen when you're not expecting it, and maybe not necessarily on a dating website.
Good luck to you!