Why do chefs in cooking shows not always seem to do things the "right" way?

I have a couple of observations:

1. "Different" doesn't always mean inferior.
2. "Best" from a science perspective, doesn't always mean most expedient in a restaurant or home kitchen.
3. Sometimes the results of the difference between "scientific" best practice, and alternate restaurant or home kitchen practice are not noticeable, unless you compare these results side by side.
4. There are lots of ways people learn how to cook, and many practices have been handed down through generations. While science is, naturally, the basis of all cooking, it is only relatively recently that people have taken a "scientific" look at cooking and shared those practices widely.

So, you are probably hearing more about "best scientific practice" these days. However, old understandings and practices are hard to give up. People typically use the practice they were taught, because it has worked for them.

One thing to realize about cooking shows and videos is that they are edited. Very rarely do they show you full details of the process, which is necessary to demonstrate a 45-minute recipe in a 3-minute clip. They may be skipping steps or simply not showing them for the purpose of brevity, even if the chef would typically use them for optimal results.

Another thing that editing obscures is that the finished product you see at the end of the clip is never the exact same food that the chef prepares earlier in the clip. At minimum there are usually three sets of ingredients used: one for the pre-cooking preparation steps, one for the actual cooking steps, and one (prepared off-screen) for the finished product to be shown. There may be many, many others depending on how the clip was assembled. In order to get a television-worthy close-up presentation for a steak, someone (paid less than the big-name celebrity) is likely cooking 3, 10, or 20 to get an optimally appealing combination of outer char/crust, marbelling, and doneness. Some shows even make this explicit - lower-budget shows or recipes prepared on infomercials might actually show the chef placing a dish in the oven and removing an identical, already-cooked dish on the next rack down. Good Eats in particular features many tongue-in-cheek jokes about "TV magic" which play on this trope.

Finally, using less scientifically validated methods (you've dubbed these "inferior", which I think is debatable) doesn't mean that the resulting dish won't still look or taste great. Scientific principles can be a good complement to cooking skill, but understanding the Maillard reaction(s) doesn't directly translate to judging how to flip a steak and when. Chefs can (and do!) use "scientifically incorrect" methods for ages, and the reason they've never questioned them is that they still obtain results that meet their criteria for quality. That's not to say that they can't be made arguably better (more consistent, more appealing, or more efficient) but ultimately you don't need to be reading food science journals to be cooking great food.

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.