K-Line couplers were identical to Kadee, and were going to reduce the price of couplers. Too bad about the bankruptcy.
As near as I can tell, kadee has about the best scale proportioned auto coupler out there. Their patent is long since lapsed, so it is surprising that they still have no competition. Why on earth would a manufacturer want to introduce an inferior coupler that will not bolt to the standard pad?
No, wait. That is a marketing decision. Most of us are not qualified to make marketing decisions. I remember walking in to my airline's marketing department to suggest that maybe going in to Palm Springs in May and pilling out in September was a bad idea. The response - get outta here. Pilots do not understand marketing. They were right.