It doesn't have to be "constant" nor "all-day". The OP doesn't say anything like that. No straw mans please.
> is just personally draining for you because you're introverted / have social anxiety
I welcome different opinions on this but I personally think that this is something to be fixed, not to be accepted. I refuse to believe that introversion & social anxiety are unchangeable character traits (at least for most people). It is not ok to be introverted nor socially anxious. But if you to choose believe that it is, you won't be able to do anything about them. As a general rule of thumb the more extrovert a person is the higher possibility of their success in life because humans are social animals. This is known. (There are of course exceptions & outliers)
> or because you have to juggle multiple responsibilities inside & outside of work and don't want the scheduling or social overhead to manage the back-and-forth
Yeah, this is fair. If this is the kind of situation one is in, one probably shouldn't pair program unless the benefits clearly outweigh the costs.
> or for any of a plethora of reasons besides "something about your process is flawed"
I see your point but I think we also need to accept that the pair programming process of a lot of companies are indeed flawed. It may or may not always be the reason but it's not wise to outright dismiss it.
> This sounds a lot like "if you have nothing to hide you don't need privacy" argument. Some people just hate pairing because it doesn't jibe with their personality or work style.
I understand this. It is just that I don't want to work with that kind of people because I in fact think that it is not healthy. For me it is a red flag to lack the basic social skills such as sitting together in front of the computer and demonstrating part of your programming skills in a live manner. The only way I would accept to work with somebody like that would be if they were a 10x programmer of something like that.
> Draft PRs + a culture of continuous reviews accomplishes much of this
No, they don't. No process can ever have the bandwidth of face to face communication so it has some benefits that no other process can offer.
In the end this is not a situation where we have to choose between PRs and pair programming. The article suggests that we can and should have both.
The key thing is to find the right balance, as it always is.
Note: I used to be the biggest introvert & socially anxious person.