Well, "yes" could seem the right answer, at first sight... but we you think about it, there's way more to it.
Videos optimization on at least four levels (the video itself, the thumbnail, the metadata (title, tags, description and such), using annotations), channel optimization, interacting with people, exploiting the power of social networks, promoting...
I ended up paying not enough attention on most of those aspects, and one of the results is that at some point, through the time, I ended up, while keeping the same average number of views, by having less comments on my YT videos.
Now, because of my personality and my attitude, I have never been that kind of person only caring about having "big numbers": one of the things I have ever appreciated the most of YT is the chance to interact with people from the whole world... and each single time a human being has told me things like - I've given this origami heart to the person I love - or - I'm making this origami flower for my mom - or, again - hey there! I've never made origami before but I needed a paper figure for a project at school... I followed your tutorial, and the origami came out very well! I got an A for that project! -... well, each single time I felt just blessed.
I know, people and their behaviours may change; and competitors are out there, trying to do their best!
Still, I'm here, determined to try to bring back those times where comments like the one above frequently made me smile.
danbergam's YouTube page