They are, but information about if a project is still actively maintained or if it's simply feature complete (data structures come to mind), should be automated in some way, otherwise information becomes stale if the maintainer of that site isn't actively maintaining it (ironically).
From what I've experienced, these sites largely go via passive maintainance, ie, based on pull requests and issues, not actively developing or updating things.
I'd love to see some kind of metric on crates.io to designate the quality of a crate. I appreciate that creating such a metric could lead to freak economics, so this is obviously not a trivial task, and the metric(s) may have to be mixed up every now and then to avoid to much gaming. Also it might be useful if such metrics are a geometric mean of the crates own score and all its dependencies.
Hardly a thing that 99% of crates are even viable for. What company would pay me 3k$ a month to full-time (or 1k$ for part-time) maintain some crate that barely anyone uses?
Only popular crates would have a chance to have support contracts like this.
The important metrics I'd be interested in is the Bus Factor, the Active Maintenance and Passive Maintenance activity as well as when the last release tag was created.
Bus Factor could be a bucketed 90-percentile count on the contributors. Active Maintenance and Passive Maintenance could be established by looking at PRs and Issues and how many commits aren't directly related to them. Last Release Tag is easy.
I agree that there be dragons, but maybe simpler metrics would be better? As an example; what if I could easily filter by crates supported by a team rather than a individual included in all its dependencies. That could be a way of doing risk mitigation. The metric would also work as incentive to create a more connected community.
From what I've experienced, these sites largely go via passive maintainance, ie, based on pull requests and issues, not actively developing or updating things.