The story I've heard is that SRAM (or some other brand) grabs the patent for reusable quick-links whenever a new chain "speed" comes out. In order not to infringe on that patent, other brands must mark theirs as one-time-use only. Of course, in reality, people find that they can re-use quick links from many brands without dying. (Ever notice that this issue seems to follow the chains with the highest number of speeds?)

If I'm wrong, I expect Cunningham's Law to kick in...