If Rockstar had such a need to replicate or show homage to these crime movies, the best way to attain that would be through a structured game, that is if their only concern was as you say "shock value their cinematic sources have", then they would be much more straightforward.
I agree. That's why in an earlier post, though not the one you quote, I point out that Rockstar is stuck between two possible contradictory ideals: the cinematic experience, and the simulation sandbox experience. I see both as results of western game tastes: the desires to replicate big-screen spectacles... but also leverage simulation technology to create "un-cinematic" virtual reality freedom. This contrast is what leads to the possible disconnect behind the story drive in most free-roaming sandbox games and the actual gameplay suggested by sandbox-style freedoms.
So the point isn't that people are getting killed in these movies which are most definitely related to the game. The point is that in GTA IV, there's the added layer of simulated free agency that the videogames, and the sandbox genre, bring to the table. The GTA games may be inspired by movies, but that's only half the story. The other half of the story is how western-style free-agency in games, along with simulation of urban environments, almost offers an opportunity to magnify the violence and acts beyond what the strictly narrated, director-controlled films do. (In fact, a prototypical sort of this real-life-situation-free-roaming game design thinking can be seen in DMA's (Rockstar North's) Body Harvest for the N64.)
Oh yeah, and take another look at Mortal Kombat. That game definitely had cinematic inspiration: a throw-back to cheesy kung-fu flicks that has been lodged in American consciousness ever since the hey-day of Bruce Lee. That's obviously not everything about the game, but don't discount the effect it had on it.
How many cinematic sources have the protagonist murdering cops, killing hookers, and hijacking cars by the butt load and running over civilians. Even some of the most brutal crime movies like Scarface didn't go near the levels that the GTA series has went.
Hookers are a convenient target in underworld movies aren't they? I mean, Eastern promises revolved around figuring out why a pregnant one was killed. A hooker's death in Godfather 2 was just the starting point for blackmail. And Taxi Driver had all the psychotic violence of a GTA game... though Jodi Foster's character was actually a beneficiary instead of a victim of the violence. You mention ScarFace, but that was one of their direct inspirations for GTA:Vice City (see quotes below). And yes, these are tamer than the acts in GTA, but I've addressed that above: that's a function of the sandbox-simulation-freedom, the other main push of western design tastes.
So at least since GTA III, Rockstar has drawn an excess of information from movies and the pop culture surrounding them. There are loads of movie touchstones, just read these excerpts from a Wired article:
For the young Brits weaned on Run DMC and The Warriors, it was a revelation.
...
Dan Houser assumed the creative reins, writing game dialog and directing star-studded voice-over sessions. Sam Houser, president and executive producer, played the charismatic visionary. He hung a poster in his office of Don Simpson, the infamous playboy producer of films like Flashdance and Top Gun.
...
Grand Theft Auto: Vice City would be a fun-house-mirror version of Florida circa 1986, drawing on TV’s Miami Vice, the film Scarface, and other ’80s iconography.
...
Voice-overs featured talent like Dennis Hopper as a seedy porn film director, Burt Reynolds as a corrupt land baron, and Philip Michael Thomas as the treacherous sidekick of the protagonist, voiced by Ray Liotta. Porn star Jenna Jameson recorded dialog for the aptly named character Candy Suxxx.
...
San Andreas is set on the West Coast in the early ’90s. The action takes place in a Boyz n the Hood-style LA, an ersatz Bay Area complete with Haight-Ashbury hippies, and a glitzy Las Vegas.
http://www.wired.com/gaming/gamingreviews/news/2007/03/FF_160_rockstar?currentPage=1Rockstar has built a reputation on pushing boundaries in gaming, and not "cinematic" boundaries.
I totally agree that Rockstar has benefitted from, and even encouraged, shock and controversy. They've been pushing buttons and boundaries ever since the beginning. But to merely label them as controversial and obsessed with titillation is to remain only at the surface of the issue. We have to move past nominal fallacy and try to trace the evolution of the GTA series, design-wise, inspiration-wise, culture-wise.
I contend that Rockstar isn't practicing original chauvinism, but instead, having drawn so heavily from a culture steeped in violence, harsh gender roles, and the virtual reality to explore that, they're instead explicitly recycling old ...well... "poisons"... under new and more powerful mechanisms.