For five years I was in a relationship from Seattle with a guy in Paris. We went back and forth every six weeks for a week. Most of our money and effort went into this.
At the end of those five years, we moved to the same place. It didn't work out like we thought it would, but it was the effort that showed itself.
It is a fallacy to say long distance relationships don't work, but you have to keep some things in mind:
1) no jealousy. It's a waste of effort and energy to be jealous. You can only be so available a long ways away.
2) regular, consistent contact. In all those years, we never once missed our appointed time to Skype. Sometimes, when we didn't feel chatty, we would take turns reading a chapter of a book to one another aloud.
3) special occasions. We were always together on birthdays, anniversary, or sad times like when someone passes away.
4) goals for the future. There has to be a light at the end of the tunnel, so it can't go on forever like this. We did it for five years but a lot of people don't.
Looking back, it was the best, conscientious thing I've ever done. You build the effort day after day.
So those people who say it can't work just can't be arsed to try. You can do it if it's worth it.