It's refreshing to see an opinion in support of downvoting that isn't purely based on greed or trying to promote some scheme. It gives me a different perspective that's worth thinking about.
I'm still getting decent rewards from posts that aren't about Steem. Maybe I'm in one of these curation circles? I normally blog about my life and most of my upvotes are random trails or curation projects.
To be honest I don't think the people you tagged will stop downvoting bid bots. They are after vote trading next.
I can't see why they wouldn't allow someome to create a tribe bidbot that is purely centered around those tokens and only accepts and votes in those tokens. The issue with tribe bidbots is they were taking Steem in exchange which seemed wrong.
The issue with bidding on Steem is everyone uses it amd they had three years to fix things with bid bots and vote selling and trading, but the price kept declining. I say we give it at least a year before concluding this destroyed Steem. In the meantime, it will be sad to see some people who were honest, but still affected like you go.
I think you should just lower your rOI expectations for awhile until you find a new niche that works.
If a tribe bot just has like 100sp to get sufficient RC for accepting and bidding in its tokens only, I'm sure no one will bother it.