As a bounty hunter always expect failures sometimes
1. Just because a golden year occurred in the past doesn't mean we will witness such again, yes it's possible but better adapt to present condition.
2. Promoting two to three projects and waiting for your payment doesn't make sense, as a bounty Hunter the sky should be your limit, since we can't tell which project will pay or not I suggest continues hunting.
3. Listed bounties may not pay, it's still same risks as bounty projects that aren't listed on exchange yet, rewards may vary but who am I to tell? I'm not a great seer am I?
4. Scammers takes advantage of Cov-19 alot and many still fall victim upon all the warnings, now we only have few days left till next Bitcoin halving, few new scam projects will surface, keep your eyes sharply opened
I do not totally agree with your 2nd point because blindly promoting and participating in bounty campaigns will encourage scammers and they will take advantage of free promotion for their scam bounties. I highy suggest due diligence and picking the top 3 or 4 campaigns at a time max. Because it is better to work for handful of campaigns where you are sure of project and reward rather than promoting dozens where you will find good projects and gokd rewards from 10 to 20 percent of them only.