I paint because I'm passionate about it, and it's like therapy for me, helps me organise my mind and stay positive. I am grateful when people like what I do, and appreciate when they take the time to tell me- and I'll send them a reply to thank them. That said, I don't mind too much if no one comments on my art. View statistics help me determine how interested people are in my art, and which paintings are the most popular; comments can provide extra insight, of course.
As Daily Paintworks is a site for selling art, there are a lot of professional artists here- running workshops, involved with galleries, minding market stalls... I am guessing they don't have much free time, and I expect they'd rather like to spend it with their spouses, kids, friends. Others have non-art jobs and responsibilities. So I don't begrudge people for not commenting.
In my mid-teens, I spent a good hour each day leaving comments on whichever art forum or gallery I was a part of at the time. I took pride in what I wrote; I tried to explain what I liked about the work, and did my best to provide critique if the artist requested it. But now, I'm studying for a degree, self-employed, and have to think about scary grown-up things like learning to drive, filing taxes, planning my future. And as I'm active on quite a few sites at once these days, my comment-time gets split between them. So I don't comment quite as much as I used to, but I do still make an effort.