The "essentially static hosting" isn't the cost centre (although with 5 million MAU, it's nothing to sneeze at). The real costs are on the input side - they have an ingestion pipeline that ensures standardised paper formatting and so on, plus at least some degree of human review.

I don't see it as an especially exuberant structure or budget. I've seen larger teams with bigger budgets struggle to maintain smaller applications.

I've contracted into some consultancy teams which you could uncharitably describe as "15 people and $4mn/yr to create one PDF per month".