Probably one of my few complaints about DA has been the fact that the smaller channels seldom Get little to no traffic even just to receive constructive criticism and to borderline ask for it you need a premium account. Hopefully this will change in the near future.
A lot people just like to look. There is so much coming in someone's inbox if they watch several people, so it's too much work to react on everything. Don't worry, your art is been seen, many people are just lazy.