The traditional role of A&R was crucial to an artist’s success. Before the internet, A&R reps were the gatekeepers. You didn’t find success in music unless an A&R rep found you. What’s happening today is A&R people will wait to see what artists are succeeding, then sign them to the label. They no longer focus on developing artists, but rather invest in artists whom they know can make the label money.
Source: What Is A&R (and Do You Need It)? – Digital Music News