Why do you need to unionize if you actually can do some job and there is a well defined social welfare? So if you can not do a job you shouldn’t be hired at all

Why do you need to unionize if you actually can do some job and there is a well defined social welfare? So if you can not do a job you shouldn’t be hired at all. If you can do a job but get laid off because of economic conditions we should push for a better social welfare system. BTW, Layoff is the natural consequence of over hire, but did you feel angry when companies are over hiring? Probably not. It means employees are just as blind as employers.