Note that cooking shows/demos are highly edited. Things like patting meat may very well be done off camera by preps, not left for a Celebrity/Exec chef to do. For searing, the point is not actually typically (at least as I was taught) to dry the meat. Rather, it is to remove the surface water. Often you will then be taught to salt and let set for a few minutes. One of many reasons is to draw out moisture which will help with getting a better sear on the meat, but it is that fresh protein infused fluid that does the trick, not older water and condensation mixed liquid you earlier wiped off. Again, that is as I was taught and works for me, and other experiences might disagree.
On eggs, that is a controversial one, but typically when you talk about salt helping retain water, you are talking when mixed in. So, a scrambled egg with salt would retain water, but a fried egg it may draw water out, weaken the yolk membrane and make the white more rubber. Seemingly contradictory statements, but it depends greatly on application.
Additional I would note on the general differences between studies of food science such as those put out by Americas Test Kitchen and Alton Brown. In some cases the science is fine, but not really applicable to use as it may take specialty equipment to do, like how many of us can actually afford to build and devote the space to a wood fire oven to get the 800F temps for he perfect pizza once a month? It is more informational as to what you are trying to get close to. In other cases, they may do a side by side test of methods, like what is the best technique for cooking a standing rib roast, but cooking one, and only one, roast each by 3-4 methods and call that definitive. No, that is not science, that is anecdotal. Science is to do that multiple times, and have other people do it multiple times, preferably blind, and get reproducible results. Blind is that those preparing, judging, etc. do not know what they are even testing or the difference in methods, they just put it in the oven, push a button, take it out and compare tastes without knowing the expected results, and do this multiple times to eliminate variations in source product, cook bias, judging bias, atmospheric conditions, etc.