Just because you do not understand it does not make those of us that have tens of thousands of hours flying in every possible kind of weather wrong.
It is NOT about having enough rudder, it is about not catching a wing tip, and the rudder blanking you get in a slip in a swept wing. In most respects it is roll authority (aileron) that is lacking in a serious crosswind. Even if you could slip enough, you would catch a wing tip. At the same time, a slip in a swept wing interrupts airflow across the rudder, compounding the problem.
Any pilot that has any modicum of experience in a swept wing aircraft will tell you the same thing: you should NEVER slip until you are in ground effect.
In the landing at ORD, if you notice, as the upwind wheel touches, the pilot brings the nose more in alignment with the runway. In a bad enough crosswind that is all you can do. Once the upwind wheel is on the ground, before the downwind wheel touches, you can swing the nose around so there is little crab left, so the side load is minimized.
If you can’t accept a professional opinion, consider the fact that one of the largest rudders ever put on an aircraft was on the B-52. It was not because of a lack of rudder that the B-52 has rotation “crab” landing gear (the crew cranks in a hand crank the angle of wind before landing - moving the direction of the main gear). They always land in a flat out crab in a crosswind. It is not because of a lack of rudder - it is because the upwind wing will be in the concrete in a crosswind slip.
Having never flown anything with a swept wing I had no clue that you couldn’t slip except in ground effect. This is not common knowledge to some of us putt putt drivers. So thanks for the info. This had been bothering me for a long time. I tried to crab in a severe cross wind one time, it is great until the very end but it turned into an almost disaster for me as I could not manage to do all 5 things at once so I went around and landed the old school way. So I have a lot of respect for the pros in that regard. I just couldn’t understand why they do it in the first place.
Thanks for the info as I try to keep learning all the time. This is very interesting to me as aviation is a hobby and a sport to me, not a profession.
PS: I was taught to fly by a guy that flew P-51B and D's in WWII. No swept wing on those tail draggers! So I guess that explains it. He told me as you turn on final and start your slip(assuming across wind)if you need to crunch the rudder all the way to the floor and there is not enough aileron to maintain runway heading then you are "out of the envelope", immediate feed back, he told in this case you need to find another runway. Seems to me finding this little nugget of info out 50 feet off the ground is a little late in the game.