The best time to promote bounties are on altcoins season ,if you are tired of one delay after the other just quit till altcoins season returns ,this is the reason why 2017 was the best year for bounty hunters
Any year is a good time to promote new project through bounty or airdrop. Irrespective of the bearish nature experienced since 2018, theor are a lot of project that has also done pretty well and can stand out with projects way back in 2017. Most of these projects that has done well also gave rewards that actually made a lot of sense to bounty hunters.