That's often true, but you have to realize that the AFC west has some really solid teams. Not fluky teams.
The Chiefs are probably the most talented team in the AFC - except they have Alex Smith. That's held them back, but Andy Reid has them going strong. I'd expect them to be good this year too, now that they have serious offensive threats like Tyreek Hill who shredded the Broncos D.
Raiders Derek Carr is now the best QB in the division and the Raiders are much improved. They should make a strong playoff push this year now that Carr is back to healthy. They were toast in the playoffs despite their 12-4 record because they lost Carr on the last regular season game.
San Diego still has Phillip Rivers but their Defense sucks a bit. They have some talented players like Joey Bosa who has 10.5 sacks his first season and is a real beast at DE. He eats Russell Okung's shorts. Well, not literally of course!
The Broncos will struggle to win this division, and will fail unless they get much better play out of their QBs!