Your question assumes there are only two reasons a question is unanswered:
- It's off-topic and the moderators are being lazy.
- We hate you and won't answer out of spite.
I can't speak for everybody but I know at least two more reasons I don't answer things:
- I don't know the answer. I don't know everything. ☹☹☹
- I just don't see the question. There are lots of other people with problems and I'm not here all the time. I have other things to do, like high-fiving bears, and doing stuff that pays for food.
Your Nook question is very niche. I don't have one and I haven't even thought about putting Ubuntu on one. I'm no help. Your Audacity question is also quite niche but Googleable, so I've answered. Aaaand your bountied question probably needs more information to be answerable, so I've commented.
You're doing roughly the right things. Keep questions updated. Add bounties if you can... But ultimately accept that not every question is going to have somebody out there that both knows the answer and sees the question.