Has turbotax indicated if these crypto exchanges will be added at some point: BlockFi, Exodus, Nexus, Voyager?

No.  At this time, there has not been specific updates to the exchanges mentioned.  However, TurboTax is the only major online tax preparer that supports importing over 1500 stock and 2,250 cryptocurrency transactions at once, directly from financial institutions, saving you time and ensuring accuracy.

Those companies must apply to be one of the IMPORT PARTNERS with the TT system and comply to certain requirements.   Ask them to apply if they are not on the current list.