I think you'll find that the comments will start to arrive once you yourself have built up more followers and have a solid body of hubs. Rome wasn't built in a day as the saying goes so be patient and continue to write. Comments are always useful and they boost morale but they're not crucial to the success of a hub. Don't worry too much at this stage in your hubbing career.
1. Write quality comments on other hubs.
2. Join groups.
3. Answer questions
4. Share your hubs with others on a regular basis.
5. Keep your content up to a high standard.
You should attract more comments.