I have been thinking about this for some time; this is not really a bug, more an issue of impractical combination of features.
- At this time, to be able to calculate the crafting cost of any item, you HAVE TO have the blueprint in the first place, since you cannot get the list of resources without it (or having crafted one already, and kept that list).
- As a consequence, to be able to reply to the crafting request of an item you have the crafting skills for (or are close to), a crafter need to BUY that blueprint, without any guaranty that this purchase will be useful (I know for a fact that some crafting requests have been made without capability to use or purchase an item, only to get an idea how much that item would cost).
- Resulting from both issues, crafters will currently only answer to crafting requests IF they ALREADY have/had the relevant blueprint, ignoring requests which they could answer otherwise.
Suggestion: make the resources list for blueprints consultable WITHOUT the need to purchase that blueprint; alternatively, make UNUSED blueprints refundable (at purchase price).