So how does Wikipedia manage to get donations? Is it just a scale problem where you needs hundreds of millions of pageviews a day to generate any meaningful number of donations?

Each time Wikipedia does a donation drive they have a thing that says "If everyone who used Wikipedia donated $1, we'd be done in 10 minutes!" (or similar). Yet these drives go on for months. The problem is that only a vanishingly small percentage of users donate.

Wikipedia has a lot more utility than a website about a current event you're gonna visit 2 or 3 times before the issue is resolved. It's a lot easier to justify that donation.