You could not unilaterally edit anonymously; your edit would have been put in a review queue.
It is good that leaving comments is hard. First off, because it was learned repeatedly, the hard way, that removing that barrier leads to ungodly amounts of literal spam. Second because even insightful comments detract from the main intended flow of using the site, which is: you find a question from a search engine, read the question and verify that it reflects what you're trying to figure out, then scroll down to the answers and learn something. The entire point is to not be a discussion forum (which is also why comments were not threaded for most of the the site's life). In fact, the site came into existence specifically because of frustration with what ends up happening on a discussion forum where people can discuss endlessly.
See, what you're saying makes some logical sense in a vacuum but it's so utterly unlike how any other website works that unless you take a huge amount of effort to explain this to people, gently, then it's not at all surprising that people just bounce off of it.