The surprising thing is that it takes so long for a thoughtful link-aggregator to manifest. https://lemmy.ml is an approach but it's more a copy of reddit with all its problems.
It seems like the people who could create it have no need to discover more thoughtful content.
One problem is that it's likely very personal. I save links and used to publish them with a line or two of commentary on my blog. But what catches my eye is probably different from what catches your eye. You can't come close to reading everything and you're certainly not wrong to decide you just don't care about some topic even if others think it's incredibly important to follow carefully.
It seems like the people who could create it have no need to discover more thoughtful content.