In my opinion, the bounty system could use a lot of work. Most of the time when I put a bounty on a question of mine, it goes unanswered and I lose the bounty that I placed on the question. I see no reason why this should be the case, as it just "penalizes" putting bounties on questions that are hard-to-answer. Ironically, these questions are typically exactly the types of questions that deserve to have big bounties (as they typically require additional rewards to draw out less common experts to answer them).
I think it's a shame that questions that are highly advanced usually get one or two upvotes and will never see a single answer. Answering a difficult obscure question currently have way less of a payout than more popular questions like "why does stirring my soup make it cooler?" And I think if someone genuinely wants to have their question answered (even if it takes months of time), there should eventually be a way of having a high enough value for answering the question that people take the effort to answer it.
Here are some suggestions for improving the current bounty system:
Reputation points charged for Bounties that doesn't receive any positively-received answers are not only refunded to the user, but the question automatically receives 5 upvotes and the question goes back on the featured list but with a higher bounty
Reward multipliers for unanswered questions. For instance, a well-received question that hasn't been answered for 2 years and has received multiple bounties should have a HUGE payoff for answering. Every time a question goes unanswered after a bounty-session, the question should have a multiplier that rewards answering that question.
More "prestige points" are awarded in the form of medals related to placing bounties. (I think way too many "power users" hoard their reputation points, which could be used to highlight questions that require more expertise) Maybe these proposed solutions are not perfect, but I think this issue should be taken seriously as I feel that this platform can have a much better system for helping