Professionals have large networks of neurons. They are sturdy and efficient from repeated use. Memory palaces help to start the construction of these large networks of neurons. Afterwards, as another commenter noted, the knowledge is deeply processed. Mnemonics are replaced by networks of meaning. It is no longer “This algorithm rhymes with tomato”, but “This algorithm is faster if the data is stored in faster hardware, but our equipment is old so we better use this other algorithm for now”.
Broadly, the progression of learning is: superficial learning, deep learning, and transfer. Check out Visible Learning: The Sequel by John Hattie for more on this.
Edit: To directly answer your question, experts have so many sturdy neural hooks on which to hang new knowledge that mnemonics become less and less necessary. Mnemonics may be particularly helpful when first learning something challenging, but are less necessary as people learn.
You could also check out a paradox called the expert paradox. We used to think memory is boxes that get filled. This idea was directly challenged by Craik and Lockhart’s Levels of Processing. Levels of processing supports the idea that “the more you know, the faster you learn”. Note that this is domain-specific. In other words, an expert in dog training won’t learn quantum mechanics faster than anyone else.
My brother has a Framework 13 and mainly uses a combination of NixOS and Windows. Most of the time he uses NixOS, but sometimes the software he needs is broken on Nix. When that happens, he reverts to a previous version of Nix or he boots onto Windows. He has Windows installed in one of the external-drive socket thingies that he keeps plugged in at all times in case he needs Windows.
Apart from the occasional broken Nix package, he has had issues with the hyper-sensitive two-finger scrolling in Gnome (which I would say is not directly a Framework or Nix problem). Also, a while back, when I bought the computer with him, we bought Oloy RAM because it was fast and cheap, but that lead to weird crashes. Framework support helped us test the sticks and eventually we sold those sticks and got the Framework-tested Crucial sticks, which solved the problem. Finally, I remember he had to be careful about not just closing the laptop but actually clicking “sleep” and then closing it, because otherwise it would get super hot and lose a lot of battery.
Despite these struggles, he recently told my Mac-loving girlfriend that he will not get a “disposable” computer. I take this to mean he will keep using his Framework laptop.