In terms of bizmodel - we're thinking about paid promotion of packages - allowing maintainers (companies and individuals) to promote their packages.

We want to limit it to a single clearly-marked promoted package for each category. Obviously, we would just surface the promoted package, but the package reviews, insights, and metrics are obviously untouched.

Obviously, users would be happy if GitHub included some of those functionalities inside the repos. However, I don't think GitHub could simply put user reviews on all repos (technically they could, but business-wise that would not be a smart decision). So even if they were to do that, and user reviews were an opt-in feature in GitHub, then you'd have reviews enabled for some packages and not for others, which is suboptimal.