I know Sunday against the Cards was bad for Dak, but I'm still not counting the Cowboys out, even without Diggs. I think they'll be in the mix as a serious contender in the NFC late December/January.
Two words why this won't happen (imo), despite how talented Herbert and those boys are: Brandon Staley.
I tend to rock with this POV, especially as we get some of these good-on-good conference matchups over the next few weeks (Miami v Buffalo, Dallas vs SF, Baltimore vs Cleveland, etc.) that separate contenders from pretenders.