Technically nothing is really changing about STEEM. I think the real answer to your question lies in Resource Credits. I don't think people really appreciate how much Resource Credits fundamentally altered Steem (for the better). RCs essentially guarantee that no matter what anyone does on the Steem blockchain, it benefits all Steem stakeholders. This is slightly simplistic, but essentially the more transactions people perform on Steem, the more RCs are consumed, and the more STEEM needs to be powered up in the aggregate. The RC algorithm ensures that the increase in demand for STEEM won't suddenly deprive people of the ability to transact, and it smooths out the user experience. So the short answer to your question is that STEEM continues doing what it does now; it regulates the consumption of network resources by ensuring that only those who have staked sufficient STEEM are capable of performing transactions. The beauty of this system is that it simplifies our task as a community: create more ways for people to have amazing experiences on Steem. SMTs are just another way of enabling people to have more delightful transactions on Steem.