他们在公司里面有门路, 而且可以分担福利以及工作签证身份等棘手的问题. 所以很多公司喜欢委托 recruiter 招 entry-level 的人. Recruiter 也会帮忙改 resume 以及准备面世的问题.

They are working on this, keep connecting with companies and have good relations with company ,know which company has openings.
Sometimes when a company really want to recruit one person, they would like to call a familiar recruiter and let him handle some of the finding stuff, so save some trouble.
even keep interviewing people for 1 month-2 month and can't find a right person can make a company feel tired.
Sometimes recruiter can have a consulting company and they hire u as H-1B and sell u to company so to earn more.
Fidning a person for one company can earn them $10K.
owning u one year and selling u can earn them more than that.
They probably will train u to get more certificates and if u have project u get paid, if not, they may or may not keep ur status,u don't get paid or have to pay urself to keep status.