This performance by the S2 for both tethered & card is not at Pro level.
My bet is that Leica can simply ignore the pro market and sell these things to wealthy amateurs. THAT is their market for this camera; not pros. There are way more wealthy amateurs out there than pros shooting tethered in a commercial studio. (Wouldn't you just love to see the market share demographics, just out of curiosity?) I'd bet it might be as high as 10:1.
Their target market will never tether, and will never come close to hitting the buffer. They'll shoot low-volume landscapes, or whatever, and probably be incredibly happy with the camera. I am dead serious.
I'm betting that, if we could ever get our paws on those top-secret demographic break-out sheets, we'd find that professional photographers that are owning
and using MF gear, and tethering, are but a tiny blip on anybody's radar. My bet is, most pros that are tethering with paying jobs are renting the whole rig either from the studio, or from a Tech. They shoot the job, hand the camera to the Tech, and wave goodbye.
This S2 is a camera to go into an Eddie Bauer Expedition, or a Range Rover. Not a Grip Truck.
Having said that, can you imagine that some Leica engineer sat there with his stopwatch, and timed Twenty Seconds before the RAW came in at a full rez, and said, "Yes, that is perfect. Much faster than 669 Polaroid! Ship it!"