Can they do things to influence games? Yes.
Are games influenced by unconscious bias also? Yes.
Are there means of tracing money and digital footprints that make organized corruption REALLY difficult? Yes.
Is football one of the most highly skilled competitive games ever with athleticism that simply cannot be faked? Yes.
So ... if you're behind the big machine in Vegas ... you can lean on things. You CANNOT control things.
So, let's say I'm the bad guy. I have 8 games each week I want to fall a certain way. I have a few refs, and maybe some coaches/players that are aware of the spread.
Then I bet the way I want, and relay the way I want things to fall.
If the games are close to the spread, maybe someone does a little something to push it. Like the Green Bay Seattle game where Golden Tate comes down with the Hail Mary. Maybe a kicker misses an extra point. Maybe bad clock management. Maybe you lose by 7 instead of 10 by kicking a late field goal.
Maybe that guy gets a marker if you think he helped you. Maybe he finds his way into some luck in the future.
I don't believe in scripted sports. I know how good football players are. I know that a game of inches cannot be controlled to that extent.
Want to say one more thing ...
Some will say that there are coincidences between teams that win and things going on in the world ... I get that. But that's unconscious bias. You don't need it to be planned. Drew Brees winning after Katrina. Tom Brady in Tampa home game. Patriots after 9-11. Giants taking down the Pats after their undefeated season ... you can't fake the David Tyree play. But you can keep it close.