It’s tricky to quantify education globally when there are different school systems that can’t be compared against each other. For example because there is no direct comparison that could be made against say… A college.
What is generally universal is university degrees but even those can vary wildly in quality. The same goes for having learned a job. Hell some countries don’t even accept university degrees from other countries because they don’t meet the local standards.
The thing about years or time spent in education is that people can spend additional years in education if they fail a class. And nine years of education may just be as good as someone who had ten years but failed in one year. It also doesn’t account for other differences like people that spent additional time in one year for additional education.
Anyhow, there is no simple way to quantify education. If you look at the percentage of people who graduated you may get a better idea but then you still need to differentiate between education systems and how many people in a given country actually got a given graduation. Even then it doesn’t tell you anything about how good the education actually is because education can be manipulated.
So… As someone who uses the all feed and that includes finding this post and subsequently interacting with it. There are reasons to use all. I use my subscriptions more as bookmarks to have an easy return path to a community should I feel the need to really check up on that particular community. I then use all to browse for interesting content to read and possibly interact with. I don’t use local because that feed gets stale with things I have already seen very fast and I don’t look at only subscribed feeds because I don’t want it to be an echo chamber of my own preferences.
I block communities that don’t interest me, can’t interact with reasonably anyways or that are simply annoying. As it is I don’t see a problem with using all since it still drives interaction via comments like this one. You can’t really restrict voting either since that creates more issues than it solves. Remember that voting on a post is interaction too even if there is no comment from someone. Perhaps that person is short of time or just doesn’t have anything to add.
At the end of the day it is personal choice how people choose to discover and interact with content.