Why do so many people go to usa when green card backlog is decades long?

Why do people take big loans and go to usa when I heard all you do is get 90 days to find a job and you need to win a lottery in h1b and then their green card backlog which is in decades . Do these people just plan to illegally stay there no matter what? Same with canada with cutoff scores so huge for Pr and australia as well? Nz and Ireland and UK are somewhat reasonable as long you find a job you get pr. And why don't people consider eastern eu like poland croatia etc? I read that after you graduate you can work literally any job and get pr as long as you learn the language? Same with Japan and Germany you learn their language and you do anything apprenticeship and you are practically guaranteed pr as long as you get a job? Or is student visa simply an excuse to get in the country and never leave?