As explained here:
What is automatic awarding?
Approximately 24 hours after the end of the bounty period, if the bounty starter has not manually awarded the bounty, the bounty may be awarded automatically.
If the bounty starter accepted an answer during the bounty period, that answer is awarded the bounty (provided that the answer was posted during the bounty period). Answers accepted before the bounty period are not eligible to be awarded the bounty automatically.
Otherwise, if there are eligible answers, the highest scoring is awarded half the bounty amount. The criteria for an answer to be eligible are:
- The answer must have been given after the bounty was started
- The answer must have a score of at least +2
- The answer must not have been written by the bounty starter
If two or more eligible answers have the same score (if their scores are tied), the oldest answer is awarded the bounty.
If neither of these conditions apply, the bounty is not awarded to any answer, and is not refunded to the bounty starter.
Regarding the specific question, I have several of those, and bounties didn't help. I guess at a certain point you can't coax more out of the community than it wants to give. I gave up on my questions, but you are welcome to offer larger bounties.
BTW, I don't think they can change the wording because exactly what will happen is unknown - answers could get votes later.