That's not what happens here. The current workers demand a higher wage and unemployed people take the job for the current wage. This is basically why unemployment exists: you can't threaten to fire people if there is no "reserve army".

That's why strikes are most powerful when there is solidarity across the working class. The Haymarket Affairs, that led to the 8h day and is celebrated at the First of May everywhere except in the US where it happened as international worker's day. There was solidarity across employed and unemployed, black and white workers so there was no other way than to listen to the demands. The bourgeoisie tries to devide us with arbitrary lines. Don't let that happen. Show solidarity with all oppressed groups and try to understand their oppression.

Do these people exist for real?

Yes, or else everyone would be in a union. They are subject to the same socio-economic pressures but either draw the wrong conclusion (capitalism is good) or just don't give a shit and will take low wage over no wage.

Sure, although a more common occurrence was bringing in soldiers or police to shoot striking workers.