I think what Sports Illustrated may have done this week is simply cut and pasted their NFC West prediction from 2018 into 2019. Last season SI thought the Rams would go 12-4, the 49ers 10-6 and the Seahawks 7-9 (no one cares about the Cardinals). SI has the same prediction for 2019. The magazine is wrong.
The NFL is mostly about two things: Head coaches and quarterbacks. Seattle has the best quarterback in the division in Russell Wilson. Put him on any other team in the division and they get better and that includes the Rams.