What an interesting topic to bring up.

Could it be that comments somehow remind us about the forums of the past?

With the exception of archives and administrative pages, every page of a forum was a thread that you could get involved with (publicly) and get responses from people. Everyone could leave a mark.
If you spent some time reading an opinion or a thread of opinions, you were rewarded with the right to participate.
Now, reading a blog post and not having that reward feels emptier.

Could it be nostalgia? Maybe.