Yeah. But think about the case of jaws. Did you need all that sub-plot to make a good movie? No. All you needed was a huge shark eating people. Sometimes what works in books doesn't work in movies. But a LOT of times, writers create sidelines and sub-plots simply because if you're not established enough, publishers won't publish short books!
Ever read
Old Man and the Sea? It's a two or three hour read
I'll bet you in the case of Shooter they just rewrote the character because they wanted Mark Wahlberg.