There are currently 7.3 million SBDs out there and I wonder if the holders are expecting a pump like it did at the end of 2017 which saw the price of SBD hit 20+ dollars on some exchanges.

I don't think that would be very smart. SPS is paying out only SBD. When the debt ratio goes below 9%, up to half of the value of author rewards will be paid out in SBD. Now that STEEM is still cheap, I think many will convert.