Of course you should post anyway. Just because most people don't want to spend 20 minutes writing an elaborate comment doesn't mean they aren't thinking or they aren't enjoying reading your answer to the question. And even if you don't get much of a reaction at first, producing good, well thought out posts will eventually earn you a reputation of a thought-provoking blogger and your readership will get bigger.
Unfortunately, blog comments don't foster a good discussion environment they way a message board will. (Coming from a message board background, I learned this the hard way.) Readers will interact with you, and with you alone. Occasionally 2 or 3 readers will get into a discussion among themselves, but the design of blog commenting makes it difficult to sustain that type of interaction.
If you have ideas for good discussions and you'd like to see a lot of people involved, I highly encourage you to suggest them in our Shared Topics
forums. That way you'll get a number of bloggers posting about your ideas, plus you'll be doing us a huge favor since Shared Topic suggestions are hard to find these days