Originally Posted by
cyccommute
...Instead of the force vectors on each pair of spokes canceling each other out, the force vectors pull in the same direction.
But outbound-under-inbound at the outer cross reduces the effects of heads-out and heads-in significantly. You've got an offset between leading and trailing spoke of one spoke diameter at say 2/3 of the spokes length from the rim. That's a tiny, tiny vector to blame a collapsed rim on.