I don’t see Boogie Nights as being a ripoff of Goodfellas. It certainly wasn’t a gangster movie (although we’ve seen other movies with a story arc of rise to power, fall from grace and then redemption). The only problem is that Boogie had a happy ending, whereas some of us know full well the real-life people did not (Dirk Diggler would’ve been reduced to doing gay pornos before succumbing to AIDS before the ‘80s was out).
I didn’t mean in terms of subject matter but style and theme. It’s about a naif and his rise and fall within an outwardly alluring subculture and its extended cast of characters. The use of music and the swirling camera are clearly derived from Scorsese’s film.