Scherzer is better than any pitcher on the Cubs or the Astros, and the Nats are definitely better at 2 and maybe 3 than the Dodgers, but the Cubs and Astros both have depth that the Nats would kill for.
The Cubs, in particular, have an entire rotation of middle of the rotation or better quality pitchers. Darvish, Quintana and Lester are all 1a to 2's.
And if the Astros can "fix" Cole, they're looking pretty similar to that and have starting caliber pitchers well beyond the 5th rotation spot.
Given the shift toward fewer innings per pitcher in a season, that kind of depth is really useful. The Dodgers are sitting pretty on that front as well.
It's going to be really interesting to see how the season plays out, because if this shift is a permanent evolution of the sport, the traditional dominant rotation (like what the Nats have) may not cut it anymore.