I don't understand it at all. Southwest is universally known as "the players cue", the ultimate in playability and quality. A few years ago I was actively setting funds aside for a purchase of a Southwest. I'm glad I didn't buy one, but if I had, I sure would have played with the original shaft. Playing with a southwest with a Predator or OB shaft, to me is like having your Bentley engine replaced by a Toyota Camry engine, or the clockwork of your Rolex by some Seiko or Citizen digital watch...It might work as well as the original parts (the Rolex will keep better time for sure, but the Bentley sure won't be as good), but it's just pointless. The clockwork/engine/ shaft is an important part of what you are paying for.
To me it's clear that the custom cue makers have missed the message here. They keep making cues for people who grew up with ivory ferrules, heavy nap and 22 oz cues with full 13+ tips. I can't remember seeing anyone serious about the game play with that kind of setup. Not one. They must all live in Asia. Maybe it's different in the States, IDK. Southwest cues have been known for their playability, because they didn't make log shafts with huge ivory ferrules and solid Ivory handle cues, but they kept the quality up. Still it's clear that now many people feel that their shafts are being outperformed by "cheap" production shafts (relative to the price of a Southwest cue).
Now I feel is a golden opportunity for the custom makers to catch up to- and improve on the production cues performance while keeping the quality up. "The next Southwest" sure won't have the old school setup, but a more modern, playable one. The shaft IS the cue IMHO. Without a good shaft, by which I mean a playable shaft with moderate or less deflection and a nice wood quality, a cue is not a proper cue. It's just a decorated piece of wood. It might be impressive, but not a proper cue. Who's going to pay 5k for a cue that they can't make a ball with, once the Ivory fossils pass over to the poolroom in the sky? Collectors who don't play the game?