Companies generally offload the expensive resources first requiring the cheaper, juniors to step up and take on more responsibilities. This is good of course, but if the junior cannot get support to learn their new responsibilities, they'll just be stressed, we'll get lower quality code and overall the morale goes down.
Junior developers do “negative work” almost by definition. They can’t work independently without guidance. If they can, they are inappropriately leveled and should be at least mid level developers.
