"Could we see a future where corporate entities purchase large amounts of Steem in order to reward customers, or for subliminal brand advertising? "
IMO yes, and its a good thing. the future of steem is in its utility as a medium of exchange for attention.
I like the fact that, the cost associated with holding Steem is high for accounts not participating enough, and it's up to the users if they would like to engage with the Corporate Entity or not (obviously now with adverts, everyone gets forced to engage, whether they want to or not)..
there is a third way besides corporations advertising and corporations holding steem or steem power (which wouldn't be appealing to them because of the 2 year commitment) . like you said SP is a unit of labor. But corporations don't normally buy the ability to do labor. They rent it.
I think a lot of people will hate it, but the key to integrating steem commercially is small and medium sized users renting out their steem power... Im actually writing now about how something like that might be done...
@sigmajin Interesting. Prompt me when you have posted...