Once again, explain Frau Merkel.
Merkel is old news.. so there is no reason to discuss here anymore.
In a few month she will be gone. (i never voted for here)
Imigration, part of the story is that Germans getting old.
And you need relative many people that are young and working. (paying)
Otherwise the System would collapse, the money to pay old peoples pension is not there

It is a bit like a Pyramid scheme. (i am no Expert on that Topic)
Second reason is that the economy is involved in Politics. (it is corruption)
Companies like to underpay there workers. Migrants work for less.
They also use power and money to influence people with the media.