Have you ever flown a real airplane?
Errr...yes. Of course wind is a factor (in fact I suggested earlier a combination of erratic autothrottle settings and changing wind speed could have combined). But it's good technique to keep the power reasonably constant on final (in fact especially in windy conditions) and while the autothrottle may have momentarily retarded the throttles back I find it difficult to believe that it took so much power off that they landed so short.