If you have essentially the same players and the same coaches then yes, in sports, past performance IS indicative of future performance.
This is why the Pats are favorites every year. It is why if the Steelers do have a down year, they'll rebound.
Obviously things like injuries can intrude and drastically change the equation. Or a team can age and lose its edge. But outside of that, past performance in football is a very good indicator of future performance. Not perfect of course.
If this wasn't true, Vegas would have nothing to base it odds/betting on. And let's face it; they're very good at it.
