martin, you have been so lucky to meet the old guard
i unfortunately never had the opportunity to meet master ma, but i have have been fortunate to meet some who did and talked to many others who met him also. their experiences were always pretty consistent, in the clips we only see a fraction of master ma's demos. when he did demonstrations, he would often push with his students then with the audience, pushing with a wide variety of skill levels if you like. in the chien chuan assn in shanghai , i think on sundays wcc had an open door policy, any one could come and push with each other (a great way to improve our skills).
my experience of the old guard was through meeting grandmaster li li qun, my grandmaster, he is the second gentleman in the yongnian clip, the one hoping about. gm li was the deputy secretary of the chien chuan boxing assn under ma and due to his old ties with the yang family and fu zhongwen he is a senoir official at the yongnian conference. i spoke to him about the hoping/stamping, which he explained is not about giving up, but about discharging into the ground and trying to re-establish central equilibrium. it is a way of trying to redirect the inertia down into the ground rather then getting pushed backwards. it does not always work , and has become overused/misunderstood and can look silly. however from personal experience, when it works it fantastic. an experienced tai ji player will be aware of what you are doing and may use this to his advantage, in this case when you stamp you will only give him more rebound energy to work with! this can be seen in the clip also!
to my knowledge when ma was young he loved sparring, this is how he met wcc! he was reputedly pretty good, all just history now i guess! ma never claimed to be superhuman, he said anyone can reach his level with hard work and perseverance. however like others had commented; to be taught by such gd teachers, to be surrounded by so many good teachers/peers, and to have the opportunity to train at a high level daily all helps a lot!
as for those who worship ma, i have not heard too much about this stuff specifically, but whats the point? what would we gain by that ? each to their own i guess!
let not forget ph is not fighting, it a stepping stone to the more advanced sparring and fighting methods of the wu style. the tai ji skills of stick adhere, join follow, do not resist or let go must be trained through ph before we can step it up! therefore looking at ph clips as real fighting, or a demonstration of such is pointless, as martin said many different aspects may be emphasized when one is demonstrating etc.
peace wassy