No. I think some relationships work better short distance, and others long distance. Long distance relationships become serious quickly, as when you go to see each other, you stay over with them. However the obvious lack of seeing each other as often can be detrimental.
It being long distance or not has a huge effect on whether or not a relationship works, but it's not always one way. I've had relationships that may have worked had they not been long distance, and one that needed to become long distance for us to realise that it wasn't meant to last.