The GOP messages in a way that, while shitty and fucked up, resonates with its base for the most part. They give them the red meat, the shit they want to hear, the dogshit policy positions they [think that they] want. Their pool of influencers amplifies that.
The Democrats message in a vapid, banal way that their base dislikes for the most part, a way that ignores or outright sneers at most of the policy positions their base wants, and makes most people think they are lizard people in costumes. Paying a bunch of influencers to amplify that does absolutely nothing but lose you more potential voters.
"Hey, you see the Republicans? Don't they suck? Vote for us! We're going to continue pouring trillions into the military industrial complex so you can never have health care or education, but at least we're not them" doesn't fucking work anymore.