On 757, main landing gear needs to be compressed for thrust reverse to actuate with throttles against the idle stop, same for ground spoilers to deploy. Reverse thrust is modulated manually, but there occurs every now and then the refusal of the engine to actually go into reverse thrust, causing the pilot to try to coax the reverse levers out of their lock detents. In the event the ground spoilers don't deploy automatically (AA SOP is spoilers armed for every landing) the PNF calls out "NO SPOILERS" and if the Captain is flying, he moves his hands from the throttles and quickly manually deploys the ground spoilers. If the FO is flying, the Captain announces "No Spoilers" and the Captain manually actuates them. If auto-brakes are armed and come on at wheel spin-up, at settings of 4 or MAX, the nose will come down rapidly. I did not detect in the video, the near instant settling/compressing, (maybe 18-24" ?) of struts that occur on touchdown with weight transferred to wheels that spoiler deployment causes. Also did not detect the quick almost nose-slam to the runway that hi level auto-brake causes.
I don't think the pilots would fail to arm spoilers or auto brakes particularly at JAC with it's high elevation, short pavement, frequently slippery far end and maybe a jet near max landing weight (ferry fuel?) as well as usually a full load of pax and equipment for the slopes.