If two people seriously identify with each other and are realistic, then it ought to last. Of course it's going to be harder when contact is so limited, but that sort of thing can happen in person if one or both of the couple have to travel for their living. I believe that the biggest struggle would be when a pair finally meet each other for a mere few weeks, or had to go long-distance after meeting first, which would make the separation too much to bear for most. That's why I think that these things need to take time and lots of careful planning.
Hell, it's certainly easier to find the ideal partner online, simply because one's scope is so limited within their area. I know nobody in person who would be able to handle half of what I'd confide in them, so I'd have to harbour a lot of damaging secrets. Besides that, I've never met anybody with whom I'd identify enough. That's why I'm happy enough to foster an online relationship until I can meet Jarby, because I know that nobody in my life would compare.
On or off the Internet, people can deceive others very easily and hide their flaws until they feel secure in the relationship. I believe that relationships here fail so much because people have unrealistic expectations or jump on each other impulsively. Aside from that, I know all too well how easy it is to become distracted from a person, with all of this community-based noise. It's not pleasant, but for me, it's worth dealing with it.