I THINK the answer to your question - is yes, there is a soft landing.
I got up to gold, but oddly enough my flights on QR dried up and all year I did nothing except take one reward flight in J. By the way, QR never bothered to send me a gold fulfilment pack. In a very subtle way, the lack of this certainly contributed to me sense of disconnection from the airline. Can't explain this but I couldn't be bothered to ring and chase it.
Anyway the inveitable happened, and I got demoted, and now I'm back at silver, but since I highly doubt I've done enough travel to merit any status whatsoever I presume this is a "soft landing".
Once back down to silver, QR was 100% efficient in sending me a fulfilment pack for that (again). Cheers