For the first job, people are accepting this level salaries but after 21 months (if you have B1 level German otherwise 33 months), you can get a permenant resident permit. At that point, a lot of people change their job and find a company which pays better salaries.

Yes, but the damage has already been done. It pushed more people on the job market exerting downward pressure on salaries.

It destroys entry-level jobs. Long gone are the days that someone could start on the helpdesk or in the QA department and work their way up into a sysadmin or a programmer. Those jobs all have been outsourced and offshored. This most hurts people who have the talent but not the formal qualifications. It is a total betrayal of social mobility by EU governments.