The Las Vegas NFL betting market is run by the big sportsbook in Nevada. They were often on TV when analysts previewed games, as Nevada was the only US state with legal sports wagering. However, many more states now allow bets after striking down a federal ban in 2018, and so Vegas NFL odds have lost some traction. Meanwhile, many sites wait for those lines to be published before they publish their own betting line; these are respected line makers who operate out of Las Vegas and have decades of experience.