There are a lot of things that go into a striker's ability to score goals. Finishing is just one of them. Attributes like pace, acc, strength, agility, anticipation, off the ball, first touch etc. are all affects a striker's ability to get into goal positions. Tecnique, composure, decisions, finisihing etc is important to turn the chances into goals.
So a good player with low finisihing can score lots of goals.