I dropped from GGL to Silver today (just under 1k TP last year as I chose to spend more time flying anyone else, mostly not OneWorld).
Nothing booked until April with BA and not really missing them. Grass is greener elsewhere, although not as lucrative status wise as of yet.
(Haven't been less than Gold or GGL for many years! Could be a shock to the system!)

Have selected seats: a couple of exit rows on domestics and rear seats in a PE cabin, but that's it.

Can survive getting moved to a bog standard seat on my MAN-LHR flights, and as long as my long haul flights aren't a middle, I'll be fine.

OK, the lounges I'll miss, but I'm sure I'll do enough with AA / Alaska / QR to get back to gold this year.