Frank,
Kumba summed it up pretty well. If you have a customer or potential customer that actually NEEDS a VOIP solution (which IS rare I admit) and you are not able to offer them what they need, then yes your are giving away work to someone who can offer what that customer needs.

Every other situation where customers think they WANT voip in some form or the other, you have 3 choices. Give them what they think they want, show them a different solution that may or may not involve voip, or walk away.