As someone who worked remote for 8 years I can see a few reasons

- Really hard to get juniors up to speed when they are remote, when I started out as a junior I sat around a bunch of senior folks, and inhaled in all the knowledge via the interactions we had all day.

- In my previous company, we hired a bunch of juniors who clearly were not self-motivated. There were few who were actively disengaged, would not even care to turn the camera on. They were a few boot-camp grads who though motivated, I could not for the life of me teach computer fundamentals. You can't learn a 4 yr degree's worth of stuff in 6 months at a bootcamp.

Yes Covid was great for us senior folks who did not need direction and were disciplined, but really bad for junior folk.