I can only imagine the anguish I'd feel over cancelling a Sig reservation after giving up 40k for years.
I got my reservation (16388) back in March, and I had enough anguish over cancelling that. Originally, I viewed the reservation as a refundable $5k option, with the only real cost the opportunity cost on the money. I went ahead in case the queue doubled in size after the release, the X turned out to be a must-have, and I was suddenly looking at a one year wait.
I was interested in the X as a replacement for 2 (possibly 3) vehicle in the "fleet": my high MPG commuter (Mini), stuff hauling/boat towing pickup, and (maybe) weekend toy (911, which I've decided to keep). But with the limited cargo capacity from the 2nd row seats and the too-low towing (I need ~6k for the boat), I'm out. I don't have a family to haul around, so a vehicle that is more people-hauler and less stuff-hauler isn't that appealing to me.
My next vehicle will be a Tesla, just not an X. I'll probably start hunting for a CPO S to tide me over until the 3 comes out (I prefer smaller cars, anyway). Hopefully I'll get in the 3 queue nice and early.
BTW - the folding Harbor Freight trailer has been mentioned upthread. I had one of those for years; it's very useful. You have to add a 4x8 plywood deck, and build your own sides if desired. It folds in half, stands up on casters, and the tongue folds down. When stashed, it takes up a footprint of about 5'x1' in the garage, and ~6' high. I attached a safety chain to the garage wall to make sure it wouldn't fall over.