I might agree that in the beginning some developers aren't as efficient as being solo. But I've yet to find someone who doesn't benefit from being forced to explain their thought process in a clear and concise manner to a coworker. It benefits the pair and it benefits "normal" communication because of that constant practice.
I've found that even for devs who are completely against, which I was one, can come around on pairing given the space and time to succeed.
It could be from a lot of the comments here around percentage of engineers not wanting any part of pairing. Cutting off parts of your job pool or even your current workforce is a tough request.
There's also incentives for individual success that soloing goes along with. Whereas pairing might lead to a greater product solution and with the lack of clarity around individual contributions. From what I've seen that's why pairing is implemented at smaller places or on separate products that are run as more of a smaller company.
Background: I was at a company that was forced into pairing and xp and said the same things about me not wanting to do it and leaving if I had to. I then tried pairing out and absolutely loved it. I moved to a larger company, for unrelated reasons, where we didn't pair and did not enjoy it. So I came back to a company that does pairing every day and I can't imagine working in an environment that doesn't pair consistently again.
I've used both jira and tracker across a few different spots and can confirm that Tracker is refreshingly lightweight.
To me, tracker is an easier user experience for focusing on a stream of stories. And a more streamlined experience for work assignment means more time writing code to solve problems.
I've found that even for devs who are completely against, which I was one, can come around on pairing given the space and time to succeed.