The minimum wage here is a lot higher than the minimum wage in Poland.
Yes. So too is a can of coke, a pack of ciggies, a pint of beer, a loaf of bread, a month's rent.

I've worked with plenty of Poles. Literally none of them went home for winter.

And the people whose strawberry farms go bust can get jobs cleaning toilets in London. Bravo.
Let me know when this actually happens, rather than it being something you imagine happening.