The big planes and small planes that get buffeted about are going very slowly and are approaching their stall speed. Right around stall is where the controls are at their least effective. They stop working altogether when the plane stalls ... well not completely, but close. The only place you are going is forward and down, hopefully with level wings, if you stall it in coordinated flight and stay on the rudder and ailerons to keep it that way.
So, the planes that "move around" just over the runway are usually at 1.2 times stall speed or less, usually less just before touchdown.
The P-51D that Dale Snodgrass was flying was probably moving at about 200 knots or more and is not very susceptible to small gusts. It DOES move around, but not much since he is moving at what would be virtually cruise speed and is into and out of gusts before they move the aircraft much. If he were going slow and were landing, it would move around, too, right before touchdown, if wind and gusts were present.
At our airshow in Chino, it is usually warm and gusty since our event is in the first week of May in Southern California, USA. The performers all KNOW that and realize they will get kicked around by wind and gusts. Nobody flies down the runway at 2 feet. The lowest altitude we fly is somewhere around 50 feet, so there is considerable room for error.
The faster you go, the less you move around. When Steve does a low pass in the F-86 at 400 knots, he isn't moving around much. When Hartley does a low pass in his Stearman with Margie on the wing at 90 knots, he moves around several feet at a time. Both fly accordingly.
When I was flying a lot in Cessna 172 / 182's, I knew exactly how much it would move around when landing. It comes with experience and there are no low-time airshow performers. All have a lot of hours behind the stick, all the ones flying aerobatics KNOW aerobatics, all have FAA waivers to fly in close proximity to the ground and the crowd if they are doing any aerobatics. The guys just flying the warbirds around don't have special waivers, but they have enough hours in the planes to fly them around in safe, non-aerobatic fashion and have been signed off in the planes. Nobody does aerobatics in our B-25, but they can land it on a spot and it goes exactly where they want it to go.
The FAA doesn't hand out credentials without a pretty thorough examination of the pilot's abilities. The people doing level passes are qualified to do them and the people doing warbird aerobatics are qualified to do aerobatics in warbirds. Sometimes mechanical woes get someone and sometimes a pilot makes a big error. There was an airshow recently where a wing walker on a Stearman was killed due to pilot error. The pilot was killed, too. He pulled before he had rolled out enough and pulled won into the grass. Though it happens, we all want the next error like that to be a long way off or never.
We take thing a step farther and require practice of the complete routine on Friday before the Saturday / Sunday shows. If anything looks "iffy" at all, adjustment s are requested by the air boss and it is flown again until there are NO issues. There is no possibility to "decline" the requested adjustments; you make them and fly it again or you don't fly in the show.
So yes, the planes landing move around a bit, but mostly when slowing for touchdown. They DO move around SOME in a flyby, but not nearly as much as when landing.