Angels and Giants are somewhat competitive. The Rockies have actually won series against tough opponents this month too. (Colorado won 7 of 11 against Diamondbacks, Cardinals and Dodgers)
Braves won 7 of 10. Nationals won 6 of 10, including two against the Mets and last night against Phillies.
I doubt the Rays and Pirates completely roll over in September. Cubs finish the season against Reds, Mets and Cardinals.
I don’t expect Chicago will sweep many series.