Yea, um, nothing wrong with mentoring and teaching but when management wants me to turn things out on a dime at the same time. Not happening. That junior is getting MINIMAL possible attention for me to work on what ultimately keeps my job not theirs.
Is that really true? Maybe some, but I don’t know about “many”. I’d imagine when most people start on their dev career, they don’t imagine their dream job to be “teaching,” they imagine it to be coding. I think you’d have a tough time getting responses for a “senior engineer” job ad that says you’ll actually be a full time mentor.
I'm just an anecdote, but if I could earn the same salary teaching and mentoring as I do as a tech lead I'd do it with very little hesitation.
This route exists, it's called training and you can earn even more doing that. Absolutely doable, but it's a long road to get there (salary- and lifestyle wise).
Even then, pair programming with a different person every day sounds awful.