Does the blockchain still need a revenue stream once the currency is being used in the real world and has value?
I would argue that any blockchain that's issuing tokens needs a revenue stream for long-term viability/sustainability. What we're dealing with in crypto aren't really "currencies." They are more like issued stock and other assets that represent a share of value in the respective blockchain. Having no revenue for a crypto token would be like issuing stocks for a company that tries to tell you, "We don't need to make any money - you have that stock certificate! If other people believe that the certificate is worth $100, then it is!"
Of course, this falls apart as soon as people simply stop "believing" in the value and actually look for valuation metrics, only to discover that there are no fundamentals.
What would have the most impact, the revenue stream itself or putting Steem out there as the Currency You Can Buy Stuff Withtm?
Network effect can have a huge impact on overall value, but having a revenue stream puts solid fundamentals behind asset value. Both are good to have, but as long as you have revenue, the network growth isn't as important.
If the companies that buy Steem for advertising will at some point also retail their products for Steem in some of their distribution channels for their marketing purposes, we'll be golden.
Yep, that's the obvious goal here. Bring in individuals/companies that want to advertise, get them involved in the ecosystem, have them sell their products and accept the Steem currencies. Create that business ecosystem that everyone is always talking about. If we want businesses, we need to accept advertising. That's how it works.
Yet. Once they are, and some could be, I am not so sure they will still need an underlying anything to be useful and valuable. Anything I can buy stuff with I see as a currency, not a stock. But never mind, that is still some way away anyway and I may be wrong.