You really think that the media wouldn't want a story about the biggest sporting league in the states being a total farce with fixed games? They would eat that crap up, they jump on every little potential "scandal" story and run with it as much as they can, often much longer than they should, including sometimes getting people who actually ARE making things up that support their story.
Every media outlet would be on the story, most major publishers and TV/Movie studios would want the story, the sponsors would be interested, there's no amount of NFL PR that would be able to beat that story if the ref actually had evidence, which would not be hard to get if it was indeed fixed (as they would need to be told who to have win each game, etc)... The NFL couldn't physically do anything to the person without huge backlash, they couldn't bury it with PR, they wouldn't be able to do anything. They would crumble, lose fans, etc. Once the story leaked there would be additional looks into the league and the books, outside groups would be doing investigations, the government would likely get involved (because they always do), there's just almost no way the NFL would be able to beat it without removing pretty much every single person in charge, including owners, officials, etc, and totally rebuilding from the ground up, in an extremely transparent way that ensured fans they were being honest, which would take years.
It's just simply not plausible. They'd need to vet incoming officials to make sure they would be okay without giving anything up, need to make sure they never even told their families (which they likely do), never were willing to go public... It's too much.