At one of the Dartmoor meets, Andy Bruce, made a group bowdrill, with gathered materials, true he used paracord for the string, but it still worked. He did have the components sat near the group fire, drying totally, for a day or so, but it worked eventually. I see what you're saying though, he had a fire to start with, to dry the timbers, and he used man made cord.
It's interesting you mention no sense of exultation from it. If you don't feel like you have actually achieved something special, then the exercise has nothing to reward you with and, as such, I would say this goes against much of what bushcraft is about. Bushcraft should be about enjoying the things you do, while you live alongside nature, in the most environmentally/nature friendly ways.
Ultimately, what I'm trying to say (just not very well
) is, I totally agree with you, that (for you and many others) the fire bow isn't a bushcraft skill. However, for the people that do enjoy it, I think it is. Purely for the fact it is an activity that makes them feel good, that they can share with like minded people, while holding onto primitive skills that our ancestors may have used and not letting the skill fade into the past.
I hope that makes sense to someone out there, my brain hurts...