So do most popular companies. they get many applicants for a job. So you have to filter those applications. One way is to recruit from known places where they

So do most popular companies. they get many applicants for a job. So you have to filter those applications. One way is to recruit from known places where they have already got people from as they know it worked. Typically those universities also filtered on how good you were and so the average quality is higher from those. Obviously there will be exceptions but not work spending time to find them. Recruitment costs a lot in time and money.