On average he's a 1 in 2 striker. He averages less than 1 shot on target per game and usually get less than 2 shots on target per game and 3 shot creating actions. That's over his whole career. His conversion rate last season was one of the best in the league.
If you look at it from that point of view, of he could get more chances, can he score more goals? The answer is probably yes.
It's obvious he needs to improve his positioning and movement. But he's young and still learning, being first choice striker at Utd right now, isn't the best environment for a player to develop. He's learning on the job, RVN didn't join Utd until he was 24/25, Andy Cole, Dwight Yorke all around their mid 20s. So, he has a lot of added pressure on his shoulders.
He also needs to have players around him who will provide the chances, Utd's wingers just aren't good enough at chance creation and more often than not make poor decisions in and around the box.