Unless other money replaces this, it’s great news for Republicans.
I'm betting other money replaces it. There's a lot of deception/disinformation that goes on at this point during a campaign. Recall that a couple weeks out from the 2000 election Bush allegedly had a poll showing him within striking distance of Gore in California, and did a coupled/few day sweep through there. There was no such poll, but it pulled Democrat $$$ and attention away from states like Tennessee, where the Bush campaign DID have good polling showing trending in Bush's direction.
Additionally, the Democrat's big-data systems (like
Catalist) may be showing that they've maximized their pre-election turnout effort there, are going to win (IOW the polls are wrong because they're not picking up on the folks whose votes will swing the election) and that they can move the money to other races.
IIRC, it’s the polls in this cycle by Fox and another outfit, which show Republicans in the lead that are the “gold standard” polls where they are polling both cells and landlines and are using live pollsters vs. robo polls.
I do agree with you though, Colorado is way too close to have Democrat money pull out of it. For me, it’s state No. 52 for the Republicans, but remains a tossup, leaning Republican.