It makes sense that some people would be more universally desireable than others for having certain qualities, but it's awfully fatalistic to say that there are "Ones" who would be "disappointed in their search for THEIR respective Ones," and that others would be "left crushed by the fact that they aren't the One for that special person." You're ignoring the fact that people grow and change.
I read your other thread (I assume you are referring to
Preserving A Platonic Friendship) and I suspect that you're extrapolating this rather simplistic rule from a very complicated situation. Give yourself more credit than that.
Speaking to this on a more general level, a person who finds himself rejected by someone he thinks is special (or The One, as you call it, though I don't believe in that concept) doesn't have to be "left crushed"... if anything, he can emulate what he admires in that other person and make it his own. As for the people you call "The Ones", well, I guess you could say it was an exercise in patience to wait until the right person(s) come along. More importantly, a lot of people might not even be searching. Sometimes being single is just right and there is no need to search for partners. Both states of existence (being single and being in a relationship) certainly have their time and place.