Performing the task of weightlifting is incredibly different than performing the task of programming. Much evidence suggests that programmers perform better solo because they can more easily reach states of psychological flow, and because they are less inhibited by social interactions which modulate certain parts of our thinking and can inhibit creativity, etc. At the very least, this is more highly true of introverted personality styles, and creating mandates for policies like pair programming is extremely insensitive (almost to a point of blatant discrimination) towards people with differing personality and learning styles.

For me personally, I can't learn anything from other people saying stuff about it audibly. I have to read documentation or code. I am the weirdo who actually reads my car's maintenance manual to figure out how to change spark plugs or use the jack to lift the car when replacing a tire. Someone can tell me how to change a tire all day long and it just doesn't help at all. I even played quarterback on my high school football team and even at that I had to actually read books and biomechanics papers about the throwing motion before I really improved. I went to football camps and everything and it just did no good. For me, I really only absorb information when I literally tune out all audio (especially the sound of people talking) and read.

I suppose I serve as something of a counter-example, then. Just because beginners in weightlifting (or any given activity) benefit most from fast, in-person feedback does not at all mean that beginners in some other activity (like programming) will also benefit from that kind of feedback.

I've also worked in high pair-programming environments, in one case with a group of other experienced, extremely talented engineers, and in another case with a larger number of average to mediocre engineers.

In both cases, across the board, pairing slowed us down and led to worker dissatisfaction. The few times when pairing came in handy were those cases when a person needed to begin working on a section of code or a subsystem that someone else had explicit experience with. Then, pairing them briefly (for, say, half a day) to force the novice to get up to speed quickly and have an "oracle" nearby was really helpful, but after about the 4 hour mark it just started slowing both people down, caused the novice to learn too slowly, and focused hyper amounts of attention on issues that wouldn't have needed to be brought up if the novice instead focused on solving their own problems and boiling down their issue list into a smaller, asynchronous list of just the most urgent needs.

And, truly, the only reason that those first four or so hours of pairing worked at all is that the documentation for the code was poor. If the exact questions and answers that were discussed during pairing had instead been turned into an internal StackOverflow and/or an internal quick start guide, it would have helped far more people get up to speed far more quickly than pairing, while only costing the senior dev a single up front cost.

Pairing is the definition of an activity that doesn't scale, and is arguably less beneficial than well written user guides + StackOverflow-like tools that allow for documenting the learning process.