Would autovoting services / bots accepting only STEEM and not SBD help with that?
If many publishers get SBD then use it to promote their posts and the SBD doesn't get exchanged by those who get it, it continues to slush around inside the system.
I suspect that an important proportion of SBD is funneled through the wallets associated with such promoting services and their operators aren't willing to part with it, neither.
The mechanism seems to be working, being designed to incentivize long-term holding, the way it is, but maybe we need a failsafe that works as a pressure safety valve forcing some conversion at some point.
I'm fairly new to the platform and I'm still learning a lot.
I, for one, will be switching to paying in STEEM whenever possible.
That's what I can do about it.
Give them STEEM, not SBD.
When we get SBD, we can convert it in STEEM and close the circle.
If we (regular users) do our part and they do theirs (promoter services), there will be more exchange from between STEEM and SBD.

I wonder if, where or how we can get the bigger picture when it comes to the actual transacted volumes over time.

Who knows more or understands this better, please chip in.

Thanks.