What I don’t understand is why people tolerate this.
Of course companies will do this and worse if people let them.
A lot of ppl on the market means we have no leverage in discussion.
Several times in my career I've had my boss or one of my boss's peers send someone's resume to me because our tenures at another company lined up. Sometimes I knew them, and sometimes someone otherwise very well qualified for a job on the technical merits didn't get an initial interview because they were horrible to work with.
they won’t let you make yourself irreplaceable
This will work only if your manager has 62 IQ.